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* Problem using dm-multipath on first of 2 LUNs on system
@ 2008-01-29 15:42 LittleJ
  2008-01-29 16:58 ` Gerald Nowitzky
  2008-01-29 19:58 ` malahal
  0 siblings, 2 replies; 7+ messages in thread
From: LittleJ @ 2008-01-29 15:42 UTC (permalink / raw)
  To: dm-devel


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I am attempting to implement dm-multipath on a RHEL4U6 server and I have
been successful in enabling it on the second of 2 LUNs on the server but
for whatever reason it will not create the device special files in
/dev/mapper for the fist LUN.  `multipath -d` shows that it identifies
the first LUN and wants to create the mpath0 files:

 

[root@svwdcvispay01 etc]# multipath -d

create: mpath0 (36005076801810085c800000000000194)

[size=12 GB][features="1 queue_if_no_path"][hwhandler="0"]

\_ round-robin 0 [prio=50]

 \_ 1:0:0:0 sda 8:0  [ready]

\_ round-robin 0 [prio=10]

 \_ 1:0:1:0 sdc 8:32 [ready]

 

switchpg: mpath1 (36005076801810085c8000000000001a2)

[size=50 GB][features="1 queue_if_no_path"][hwhandler="0"]

\_ round-robin 0 [prio=50]

 \_ 1:0:1:1 sdd 8:48 [active][ready]

\_ round-robin 0 [prio=10]

 \_ 1:0:0:1 sdb 8:16 [active][ready]

 

[root@svwdcvispay01 etc]#

 

 

However `multipath -v3` generates a "set ACT_CREATE: map does not
exists" error in the mpath0 section:

 

[root@svwdcvispay01 etc]# multipath -v3

load path identifiers cache

#

# all paths in cache :

#

36005076801810085c800000000000194  1:0:0:0 sda 8:0   IBM     /2145

36005076801810085c8000000000001a2  1:0:0:1 sdb 8:16 10 [active] IBM
/2145

36005076801810085c800000000000194  1:0:1:0 sdc 8:32   IBM     /2145

36005076801810085c8000000000001a2  1:0:1:1 sdd 8:48 50 [active] IBM
/2145

dm-0 blacklisted

dm-1 blacklisted

dm-2 blacklisted

dm-3 blacklisted

dm-4 blacklisted

md0 blacklisted

ram0 blacklisted

ram10 blacklisted

ram11 blacklisted

ram12 blacklisted

ram13 blacklisted

ram14 blacklisted

ram15 blacklisted

ram1 blacklisted

ram2 blacklisted

ram3 blacklisted

ram4 blacklisted

ram5 blacklisted

ram6 blacklisted

ram7 blacklisted

ram8 blacklisted

ram9 blacklisted

===== path info sda (mask 0x1f) =====

bus = 1

dev_t = 8:0

size = 25165824

vendor = IBM

product = 2145

rev = 0000

h:b:t:l = 1:0:0:0

tgt_node_name = 0x50050768010010b9

serial = 020060402172XX00

path checker = tur (controler setting)

state = 2

getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)

prio = 50

uid = 36005076801810085c800000000000194 (cache)

===== path info sdb (mask 0x1f) =====

bus = 1

dev_t = 8:16

size = 104857600

vendor = IBM

product = 2145

rev = 0000

h:b:t:l = 1:0:0:1

tgt_node_name = 0x50050768010010b9

serial = 020060402172XX00

path checker = tur (controler setting)

state = 2

getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)

prio = 10

uid = 36005076801810085c8000000000001a2 (cache)

===== path info sdc (mask 0x1f) =====

bus = 1

dev_t = 8:32

size = 25165824

vendor = IBM

product = 2145

rev = 0000

h:b:t:l = 1:0:1:0

tgt_node_name = 0x5005076801001082

serial = 020060402172XX00

path checker = tur (controler setting)

state = 2

getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)

prio = 10

uid = 36005076801810085c800000000000194 (cache)

===== path info sdd (mask 0x1f) =====

bus = 1

dev_t = 8:48

size = 104857600

vendor = IBM

product = 2145

rev = 0000

h:b:t:l = 1:0:1:1

tgt_node_name = 0x5005076801001082

serial = 020060402172XX00

path checker = tur (controler setting)

state = 2

getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)

prio = 50

uid = 36005076801810085c8000000000001a2 (cache)

#

# all paths :

#

36005076801810085c800000000000194  1:0:0:0 sda 8:0 50 [ready] IBM
/2145

36005076801810085c8000000000001a2  1:0:0:1 sdb 8:16 10 [active][ready]
IBM

36005076801810085c800000000000194  1:0:1:0 sdc 8:32 10 [ready] IBM
/2145

36005076801810085c8000000000001a2  1:0:1:1 sdd 8:48 50 [active][ready]
IBM

params = 1 queue_if_no_path 0 2 1 round-robin 0 1 1 8:48 1000
round-robin 0 1 1 8:16 1000

status = 1 0 0 2 1 A 0 1 0 8:48 A 0 E 0 1 0 8:16 A 0

Found matching wwid [36005076801810085c800000000000194] in bindings
file.

Setting alias to mpath0

pgpolicy = group_by_prio (controler setting)

selector = round-robin 0 (internal default)

features = 1 queue_if_no_path (controler setting)

hwhandler = 0 (controler setting)

rr_weight = 1 (internal default)

rr_min_io = 1000 (config file default)

no_path_retry = NONE (internal default)

pg_timeout = NONE (internal default)

0 25165824 multipath 1 queue_if_no_path 0 2 1 round-robin 0 1 1 8:0 1000
round-robin 0 1 1 8:32 1000

set ACT_CREATE: map does not exists

Found matching wwid [36005076801810085c8000000000001a2] in bindings
file.

Setting alias to mpath1

pgpolicy = group_by_prio (controler setting)

selector = round-robin 0 (internal default)

features = 1 queue_if_no_path (controler setting)

hwhandler = 0 (controler setting)

rr_weight = 1 (internal default)

rr_min_io = 1000 (config file default)

no_path_retry = NONE (internal default)

pg_timeout = NONE (internal default)

0 104857600 multipath 1 queue_if_no_path 0 2 1 round-robin 0 1 1 8:48
1000 round-robin 0 1 1 8:16 1000

set ACT_NOTHING: map unchanged

[root@svwdcvispay01 etc]#

 

 

And notice that no /dev/mapper/mpath0 device special files were created:

 

[root@svwdcvispay01 etc]# ls -la /dev/mapper

total 0

drwxr-xr-x  2 root root     160 Jan 29 09:53 .

drwxr-xr-x  9 root root    4900 Jan 29 09:51 ..

crw-------  1 root root  10, 63 Jan 21 16:15 control

brw-rw----  1 root disk 253,  0 Jan 21 16:15 mpath1

brw-rw----  1 root disk 253,  1 Jan 21 16:15 mpath1p1

brw-rw----  1 root disk 253,  2 Jan 21 16:15 mpath1p2

brw-rw----  1 root disk 253,  3 Jan 21 16:15 mpath1p3

brw-rw----  1 root disk 253,  4 Jan 21 16:15 mpath1p5

[root@svwdcvispay01 etc]#

 

My /etc/multipath.conf file is basic but I have tried creating an alias
entry that looks like "multipaths {multipath {wwid
36005076801810085c800000000000194 alias os}}" for the first LUN but the
results are the same, it still won't create any device special files for
the first LUN.

 

[root@svwdcvispay01 mapper]# cat /etc/multipath.conf | grep -v "#"

 

defaults {

        user_friendly_names yes

}

 

[root@svwdcvispay01 mapper]#

 

I have been working this issue for over a week with IBM and RedHat tech
support and they have been unhelpful.  I need to get this functional
because the server in question has been unstable using a single path to
the SAN due to stability issues we have had periodically with one of the
SAN Volume Controllers.  If additional information is needed to
troubleshoot this please let me know.

 

Joe little

littlej@ae.com

 


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^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: Problem using dm-multipath on first of 2 LUNs on system
  2008-01-29 15:42 Problem using dm-multipath on first of 2 LUNs on system LittleJ
@ 2008-01-29 16:58 ` Gerald Nowitzky
  2008-01-29 17:17   ` LittleJ
  2008-01-29 19:58 ` malahal
  1 sibling, 1 reply; 7+ messages in thread
From: Gerald Nowitzky @ 2008-01-29 16:58 UTC (permalink / raw)
  To: device-mapper development


[-- Attachment #1.1: Type: text/plain, Size: 7608 bytes --]

try and remove dm-0 to dm-4 from the blacklist. The devices in /dev/mapper are links to /dev/dm-x
(Gerald)
  ----- Original Message ----- 
  From: LittleJ@AE.com 
  To: dm-devel@redhat.com 
  Sent: Tuesday, January 29, 2008 4:42 PM
  Subject: [dm-devel] Problem using dm-multipath on first of 2 LUNs on system


  I am attempting to implement dm-multipath on a RHEL4U6 server and I have been successful in enabling it on the second of 2 LUNs on the server but for whatever reason it will not create the device special files in /dev/mapper for the fist LUN.  `multipath -d` shows that it identifies the first LUN and wants to create the mpath0 files:

   

  [root@svwdcvispay01 etc]# multipath -d

  create: mpath0 (36005076801810085c800000000000194)

  [size=12 GB][features="1 queue_if_no_path"][hwhandler="0"]

  \_ round-robin 0 [prio=50]

   \_ 1:0:0:0 sda 8:0  [ready]

  \_ round-robin 0 [prio=10]

   \_ 1:0:1:0 sdc 8:32 [ready]

   

  switchpg: mpath1 (36005076801810085c8000000000001a2)

  [size=50 GB][features="1 queue_if_no_path"][hwhandler="0"]

  \_ round-robin 0 [prio=50]

   \_ 1:0:1:1 sdd 8:48 [active][ready]

  \_ round-robin 0 [prio=10]

   \_ 1:0:0:1 sdb 8:16 [active][ready]

   

  [root@svwdcvispay01 etc]#

   

   

  However `multipath -v3` generates a "set ACT_CREATE: map does not exists" error in the mpath0 section:

   

  [root@svwdcvispay01 etc]# multipath -v3

  load path identifiers cache

  #

  # all paths in cache :

  #

  36005076801810085c800000000000194  1:0:0:0 sda 8:0   IBM     /2145

  36005076801810085c8000000000001a2  1:0:0:1 sdb 8:16 10 [active] IBM     /2145

  36005076801810085c800000000000194  1:0:1:0 sdc 8:32   IBM     /2145

  36005076801810085c8000000000001a2  1:0:1:1 sdd 8:48 50 [active] IBM     /2145

  dm-0 blacklisted

  dm-1 blacklisted

  dm-2 blacklisted

  dm-3 blacklisted

  dm-4 blacklisted

  md0 blacklisted

  ram0 blacklisted

  ram10 blacklisted

  ram11 blacklisted

  ram12 blacklisted

  ram13 blacklisted

  ram14 blacklisted

  ram15 blacklisted

  ram1 blacklisted

  ram2 blacklisted

  ram3 blacklisted

  ram4 blacklisted

  ram5 blacklisted

  ram6 blacklisted

  ram7 blacklisted

  ram8 blacklisted

  ram9 blacklisted

  ===== path info sda (mask 0x1f) =====

  bus = 1

  dev_t = 8:0

  size = 25165824

  vendor = IBM

  product = 2145

  rev = 0000

  h:b:t:l = 1:0:0:0

  tgt_node_name = 0x50050768010010b9

  serial = 020060402172XX00

  path checker = tur (controler setting)

  state = 2

  getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)

  prio = 50

  uid = 36005076801810085c800000000000194 (cache)

  ===== path info sdb (mask 0x1f) =====

  bus = 1

  dev_t = 8:16

  size = 104857600

  vendor = IBM

  product = 2145

  rev = 0000

  h:b:t:l = 1:0:0:1

  tgt_node_name = 0x50050768010010b9

  serial = 020060402172XX00

  path checker = tur (controler setting)

  state = 2

  getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)

  prio = 10

  uid = 36005076801810085c8000000000001a2 (cache)

  ===== path info sdc (mask 0x1f) =====

  bus = 1

  dev_t = 8:32

  size = 25165824

  vendor = IBM

  product = 2145

  rev = 0000

  h:b:t:l = 1:0:1:0

  tgt_node_name = 0x5005076801001082

  serial = 020060402172XX00

  path checker = tur (controler setting)

  state = 2

  getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)

  prio = 10

  uid = 36005076801810085c800000000000194 (cache)

  ===== path info sdd (mask 0x1f) =====

  bus = 1

  dev_t = 8:48

  size = 104857600

  vendor = IBM

  product = 2145

  rev = 0000

  h:b:t:l = 1:0:1:1

  tgt_node_name = 0x5005076801001082

  serial = 020060402172XX00

  path checker = tur (controler setting)

  state = 2

  getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)

  prio = 50

  uid = 36005076801810085c8000000000001a2 (cache)

  #

  # all paths :

  #

  36005076801810085c800000000000194  1:0:0:0 sda 8:0 50 [ready] IBM     /2145

  36005076801810085c8000000000001a2  1:0:0:1 sdb 8:16 10 [active][ready] IBM

  36005076801810085c800000000000194  1:0:1:0 sdc 8:32 10 [ready] IBM     /2145

  36005076801810085c8000000000001a2  1:0:1:1 sdd 8:48 50 [active][ready] IBM

  params = 1 queue_if_no_path 0 2 1 round-robin 0 1 1 8:48 1000 round-robin 0 1 1 8:16 1000

  status = 1 0 0 2 1 A 0 1 0 8:48 A 0 E 0 1 0 8:16 A 0

  Found matching wwid [36005076801810085c800000000000194] in bindings file.

  Setting alias to mpath0

  pgpolicy = group_by_prio (controler setting)

  selector = round-robin 0 (internal default)

  features = 1 queue_if_no_path (controler setting)

  hwhandler = 0 (controler setting)

  rr_weight = 1 (internal default)

  rr_min_io = 1000 (config file default)

  no_path_retry = NONE (internal default)

  pg_timeout = NONE (internal default)

  0 25165824 multipath 1 queue_if_no_path 0 2 1 round-robin 0 1 1 8:0 1000 round-robin 0 1 1 8:32 1000

  set ACT_CREATE: map does not exists

  Found matching wwid [36005076801810085c8000000000001a2] in bindings file.

  Setting alias to mpath1

  pgpolicy = group_by_prio (controler setting)

  selector = round-robin 0 (internal default)

  features = 1 queue_if_no_path (controler setting)

  hwhandler = 0 (controler setting)

  rr_weight = 1 (internal default)

  rr_min_io = 1000 (config file default)

  no_path_retry = NONE (internal default)

  pg_timeout = NONE (internal default)

  0 104857600 multipath 1 queue_if_no_path 0 2 1 round-robin 0 1 1 8:48 1000 round-robin 0 1 1 8:16 1000

  set ACT_NOTHING: map unchanged

  [root@svwdcvispay01 etc]#

   

   

  And notice that no /dev/mapper/mpath0 device special files were created:

   

  [root@svwdcvispay01 etc]# ls -la /dev/mapper

  total 0

  drwxr-xr-x  2 root root     160 Jan 29 09:53 .

  drwxr-xr-x  9 root root    4900 Jan 29 09:51 ..

  crw-------  1 root root  10, 63 Jan 21 16:15 control

  brw-rw----  1 root disk 253,  0 Jan 21 16:15 mpath1

  brw-rw----  1 root disk 253,  1 Jan 21 16:15 mpath1p1

  brw-rw----  1 root disk 253,  2 Jan 21 16:15 mpath1p2

  brw-rw----  1 root disk 253,  3 Jan 21 16:15 mpath1p3

  brw-rw----  1 root disk 253,  4 Jan 21 16:15 mpath1p5

  [root@svwdcvispay01 etc]#

   

My /etc/multipath.conf file is basic but I have tried creating an alias entry that looks like "multipaths {multipath {wwid   36005076801810085c800000000000194 alias os}}" for the first LUN but the results are the same, it still won't create any device special files for the first LUN. 

  [root@svwdcvispay01 mapper]# cat /etc/multipath.conf | grep -v "#"

   

  defaults {

          user_friendly_names yes

  }

   

  [root@svwdcvispay01 mapper]#

   

  I have been working this issue for over a week with IBM and RedHat tech support and they have been unhelpful.  I need to get this functional because the server in question has been unstable using a single path to the SAN due to stability issues we have had periodically with one of the SAN Volume Controllers.  If additional information is needed to troubleshoot this please let me know.

   

  Joe little

  littlej@ae.com

   



------------------------------------------------------------------------------


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^ permalink raw reply	[flat|nested] 7+ messages in thread

* RE: Problem using dm-multipath on first of 2 LUNs on system
  2008-01-29 16:58 ` Gerald Nowitzky
@ 2008-01-29 17:17   ` LittleJ
  2008-01-29 18:57     ` Chandra Seetharaman
  0 siblings, 1 reply; 7+ messages in thread
From: LittleJ @ 2008-01-29 17:17 UTC (permalink / raw)
  To: dm-devel


[-- Attachment #1.1: Type: text/plain, Size: 12018 bytes --]

I am not specifically blacklisting the /dev/dm-X devices.  The 5
/dev/dm-X devices on my system correspond to the 5 device special files
in /dev/mapper on the second LUN that dm-multipath is currently
managing.

 

[root@svwdcvispay01 ~]# cd /dev/mapper

[root@svwdcvispay01 mapper]# ls -la

total 0

drwxr-xr-x  2 root root     160 Jan 29 11:47 .

drwxr-xr-x  9 root root    4900 Jan 29 11:44 ..

crw-------  1 root root  10, 63 Jan 29 11:44 control

brw-rw----  1 root disk 253,  0 Jan 29 11:44 mpath1

brw-rw----  1 root disk 253,  1 Jan 29 11:44 mpath1p1

brw-rw----  1 root disk 253,  2 Jan 29 11:44 mpath1p2

brw-rw----  1 root disk 253,  3 Jan 29 11:44 mpath1p3

brw-rw----  1 root disk 253,  4 Jan 29 11:44 mpath1p5

[root@svwdcvispay01 mapper]# ls -la /dev/dm*

brw-r-----  1 root root 253, 0 Jan 29 11:44 /dev/dm-0

brw-r-----  1 root root 253, 1 Jan 29 11:44 /dev/dm-1

brw-r-----  1 root root 253, 2 Jan 29 11:44 /dev/dm-2

brw-r-----  1 root root 253, 3 Jan 29 11:44 /dev/dm-3

brw-r-----  1 root root 253, 4 Jan 29 11:44 /dev/dm-4

[root@svwdcvispay01 mapper]#

 

I believe that dm-multipath is internally blacklisting those devices.
Notice if I execute `dmsetup remove_all` which removes all the
/dev/mapper/mpath1* files and then recreate them that dm-multipath
creates 5 new /dev/dm-* files:

 

[root@svwdcvispay01 mapper]# dmsetup remove_all

[root@svwdcvispay01 mapper]# ls -la

total 0

drwxr-xr-x  2 root root     60 Jan 29 12:09 .

drwxr-xr-x  9 root root   4900 Jan 29 11:44 ..

crw-------  1 root root 10, 63 Jan 29 11:44 control

 

[root@svwdcvispay01 mapper]# ls -la /dev/dm*

brw-r-----  1 root root 253, 0 Jan 29 11:44 /dev/dm-0

brw-r-----  1 root root 253, 1 Jan 29 11:44 /dev/dm-1

brw-r-----  1 root root 253, 2 Jan 29 11:44 /dev/dm-2

brw-r-----  1 root root 253, 3 Jan 29 11:44 /dev/dm-3

brw-r-----  1 root root 253, 4 Jan 29 11:44 /dev/dm-4

 

[root@svwdcvispay01 mapper]# multipath

create: mpath1 (36005076801810085c8000000000001a2)

[size=50 GB][features="1 queue_if_no_path"][hwhandler="0"]

\_ round-robin 0 [prio=50]

 \_ 1:0:1:1 sdd 8:48 [ready]

\_ round-robin 0 [prio=10]

 \_ 1:0:0:1 sdb 8:16 [ready]

 

[root@svwdcvispay01 mapper]# ls -la

total 0

drwxr-xr-x  2 root root     160 Jan 29 12:09 .

drwxr-xr-x  9 root root    5000 Jan 29 12:09 ..

crw-------  1 root root  10, 63 Jan 29 11:44 control

brw-rw----  1 root disk 253,  5 Jan 29 12:09 mpath1

brw-rw----  1 root disk 253,  6 Jan 29 12:09 mpath1p1

brw-rw----  1 root disk 253,  7 Jan 29 12:09 mpath1p2

brw-rw----  1 root disk 253,  8 Jan 29 12:09 mpath1p3

brw-rw----  1 root disk 253,  9 Jan 29 12:09 mpath1p5

 

[root@svwdcvispay01 mapper]# ls -la /dev/dm*

brw-r-----  1 root root 253, 0 Jan 29 11:44 /dev/dm-0

brw-r-----  1 root root 253, 1 Jan 29 11:44 /dev/dm-1

brw-r-----  1 root root 253, 2 Jan 29 11:44 /dev/dm-2

brw-r-----  1 root root 253, 3 Jan 29 11:44 /dev/dm-3

brw-r-----  1 root root 253, 4 Jan 29 11:44 /dev/dm-4

brw-r-----  1 root root 253, 5 Jan 29 12:09 /dev/dm-5

brw-r-----  1 root root 253, 6 Jan 29 12:09 /dev/dm-6

brw-r-----  1 root root 253, 7 Jan 29 12:09 /dev/dm-7

brw-r-----  1 root root 253, 8 Jan 29 12:09 /dev/dm-8

brw-r-----  1 root root 253, 9 Jan 29 12:09 /dev/dm-9

[root@svwdcvispay01 mapper]# 

 

Notice also that the blacklist has been automatically extended to cover
the 5 new /dev/dm-X devices:

 

[root@svwdcvispay01 mapper]# multipath -v3 | more

load path identifiers cache

#

# all paths in cache :

#

36005076801810085c800000000000194  1:0:0:0 sda 8:0   IBM     /2145

36005076801810085c8000000000001a2  1:0:0:1 sdb 8:16 10 [active] IBM
/2145

36005076801810085c800000000000194  1:0:1:0 sdc 8:32   IBM     /2145

36005076801810085c8000000000001a2  1:0:1:1 sdd 8:48 50 [active] IBM
/2145

dm-0 blacklisted

dm-1 blacklisted

dm-2 blacklisted

dm-3 blacklisted

dm-4 blacklisted

dm-5 blacklisted

dm-6 blacklisted

dm-7 blacklisted

dm-8 blacklisted

dm-9 blacklisted

...

 

When I reboot the server dm-5 through dm-9 are gone and it is again
using dm-0 through dm-4.

 

Joe Little

littlej@ae.com

 

 

 

 

________________________________

From: dm-devel-bounces@redhat.com [mailto:dm-devel-bounces@redhat.com]
On Behalf Of Gerald Nowitzky
Sent: Tuesday, January 29, 2008 11:59 AM
To: device-mapper development
Subject: Re: [dm-devel] Problem using dm-multipath on first of 2 LUNs on
system

 

try and remove dm-0 to dm-4 from the blacklist. The devices in
/dev/mapper are links to /dev/dm-x

(Gerald)

	----- Original Message ----- 

	From: LittleJ@AE.com 

	To: dm-devel@redhat.com 

	Sent: Tuesday, January 29, 2008 4:42 PM

	Subject: [dm-devel] Problem using dm-multipath on first of 2
LUNs on system

	 

	I am attempting to implement dm-multipath on a RHEL4U6 server
and I have been successful in enabling it on the second of 2 LUNs on the
server but for whatever reason it will not create the device special
files in /dev/mapper for the fist LUN.  `multipath -d` shows that it
identifies the first LUN and wants to create the mpath0 files:

	 

	[root@svwdcvispay01 etc]# multipath -d

	create: mpath0 (36005076801810085c800000000000194)

	[size=12 GB][features="1 queue_if_no_path"][hwhandler="0"]

	\_ round-robin 0 [prio=50]

	 \_ 1:0:0:0 sda 8:0  [ready]

	\_ round-robin 0 [prio=10]

	 \_ 1:0:1:0 sdc 8:32 [ready]

	 

	switchpg: mpath1 (36005076801810085c8000000000001a2)

	[size=50 GB][features="1 queue_if_no_path"][hwhandler="0"]

	\_ round-robin 0 [prio=50]

	 \_ 1:0:1:1 sdd 8:48 [active][ready]

	\_ round-robin 0 [prio=10]

	 \_ 1:0:0:1 sdb 8:16 [active][ready]

	 

	[root@svwdcvispay01 etc]#

	 

	 

	However `multipath -v3` generates a "set ACT_CREATE: map does
not exists" error in the mpath0 section:

	 

	[root@svwdcvispay01 etc]# multipath -v3

	load path identifiers cache

	#

	# all paths in cache :

	#

	36005076801810085c800000000000194  1:0:0:0 sda 8:0   IBM
/2145

	36005076801810085c8000000000001a2  1:0:0:1 sdb 8:16 10 [active]
IBM     /2145

	36005076801810085c800000000000194  1:0:1:0 sdc 8:32   IBM
/2145

	36005076801810085c8000000000001a2  1:0:1:1 sdd 8:48 50 [active]
IBM     /2145

	dm-0 blacklisted

	dm-1 blacklisted

	dm-2 blacklisted

	dm-3 blacklisted

	dm-4 blacklisted

	md0 blacklisted

	ram0 blacklisted

	ram10 blacklisted

	ram11 blacklisted

	ram12 blacklisted

	ram13 blacklisted

	ram14 blacklisted

	ram15 blacklisted

	ram1 blacklisted

	ram2 blacklisted

	ram3 blacklisted

	ram4 blacklisted

	ram5 blacklisted

	ram6 blacklisted

	ram7 blacklisted

	ram8 blacklisted

	ram9 blacklisted

	===== path info sda (mask 0x1f) =====

	bus = 1

	dev_t = 8:0

	size = 25165824

	vendor = IBM

	product = 2145

	rev = 0000

	h:b:t:l = 1:0:0:0

	tgt_node_name = 0x50050768010010b9

	serial = 020060402172XX00

	path checker = tur (controler setting)

	state = 2

	getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)

	prio = 50

	uid = 36005076801810085c800000000000194 (cache)

	===== path info sdb (mask 0x1f) =====

	bus = 1

	dev_t = 8:16

	size = 104857600

	vendor = IBM

	product = 2145

	rev = 0000

	h:b:t:l = 1:0:0:1

	tgt_node_name = 0x50050768010010b9

	serial = 020060402172XX00

	path checker = tur (controler setting)

	state = 2

	getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)

	prio = 10

	uid = 36005076801810085c8000000000001a2 (cache)

	===== path info sdc (mask 0x1f) =====

	bus = 1

	dev_t = 8:32

	size = 25165824

	vendor = IBM

	product = 2145

	rev = 0000

	h:b:t:l = 1:0:1:0

	tgt_node_name = 0x5005076801001082

	serial = 020060402172XX00

	path checker = tur (controler setting)

	state = 2

	getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)

	prio = 10

	uid = 36005076801810085c800000000000194 (cache)

	===== path info sdd (mask 0x1f) =====

	bus = 1

	dev_t = 8:48

	size = 104857600

	vendor = IBM

	product = 2145

	rev = 0000

	h:b:t:l = 1:0:1:1

	tgt_node_name = 0x5005076801001082

	serial = 020060402172XX00

	path checker = tur (controler setting)

	state = 2

	getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)

	prio = 50

	uid = 36005076801810085c8000000000001a2 (cache)

	#

	# all paths :

	#

	36005076801810085c800000000000194  1:0:0:0 sda 8:0 50 [ready]
IBM     /2145

	36005076801810085c8000000000001a2  1:0:0:1 sdb 8:16 10
[active][ready] IBM

	36005076801810085c800000000000194  1:0:1:0 sdc 8:32 10 [ready]
IBM     /2145

	36005076801810085c8000000000001a2  1:0:1:1 sdd 8:48 50
[active][ready] IBM

	params = 1 queue_if_no_path 0 2 1 round-robin 0 1 1 8:48 1000
round-robin 0 1 1 8:16 1000

	status = 1 0 0 2 1 A 0 1 0 8:48 A 0 E 0 1 0 8:16 A 0

	Found matching wwid [36005076801810085c800000000000194] in
bindings file.

	Setting alias to mpath0

	pgpolicy = group_by_prio (controler setting)

	selector = round-robin 0 (internal default)

	features = 1 queue_if_no_path (controler setting)

	hwhandler = 0 (controler setting)

	rr_weight = 1 (internal default)

	rr_min_io = 1000 (config file default)

	no_path_retry = NONE (internal default)

	pg_timeout = NONE (internal default)

	0 25165824 multipath 1 queue_if_no_path 0 2 1 round-robin 0 1 1
8:0 1000 round-robin 0 1 1 8:32 1000

	set ACT_CREATE: map does not exists

	Found matching wwid [36005076801810085c8000000000001a2] in
bindings file.

	Setting alias to mpath1

	pgpolicy = group_by_prio (controler setting)

	selector = round-robin 0 (internal default)

	features = 1 queue_if_no_path (controler setting)

	hwhandler = 0 (controler setting)

	rr_weight = 1 (internal default)

	rr_min_io = 1000 (config file default)

	no_path_retry = NONE (internal default)

	pg_timeout = NONE (internal default)

	0 104857600 multipath 1 queue_if_no_path 0 2 1 round-robin 0 1 1
8:48 1000 round-robin 0 1 1 8:16 1000

	set ACT_NOTHING: map unchanged

	[root@svwdcvispay01 etc]#

	 

	 

	And notice that no /dev/mapper/mpath0 device special files were
created:

	 

	[root@svwdcvispay01 etc]# ls -la /dev/mapper

	total 0

	drwxr-xr-x  2 root root     160 Jan 29 09:53 .

	drwxr-xr-x  9 root root    4900 Jan 29 09:51 ..

	crw-------  1 root root  10, 63 Jan 21 16:15 control

	brw-rw----  1 root disk 253,  0 Jan 21 16:15 mpath1

	brw-rw----  1 root disk 253,  1 Jan 21 16:15 mpath1p1

	brw-rw----  1 root disk 253,  2 Jan 21 16:15 mpath1p2

	brw-rw----  1 root disk 253,  3 Jan 21 16:15 mpath1p3

	brw-rw----  1 root disk 253,  4 Jan 21 16:15 mpath1p5

	[root@svwdcvispay01 etc]#

	 

	My /etc/multipath.conf file is basic but I have tried creating
an alias entry that looks like "multipaths {multipath {wwid
36005076801810085c800000000000194 alias os}}" for the first LUN but the
results are the same, it still won't create any device special files for
the first LUN.

	 

	[root@svwdcvispay01 mapper]# cat /etc/multipath.conf | grep -v
"#"

	 

	defaults {

	        user_friendly_names yes

	}

	 

	[root@svwdcvispay01 mapper]#

	 

	I have been working this issue for over a week with IBM and
RedHat tech support and they have been unhelpful.  I need to get this
functional because the server in question has been unstable using a
single path to the SAN due to stability issues we have had periodically
with one of the SAN Volume Controllers.  If additional information is
needed to troubleshoot this please let me know.

	 

	Joe little

	littlej@ae.com

	 

	
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^ permalink raw reply	[flat|nested] 7+ messages in thread

* RE: Problem using dm-multipath on first of 2 LUNs on system
  2008-01-29 17:17   ` LittleJ
@ 2008-01-29 18:57     ` Chandra Seetharaman
  2008-01-29 21:24       ` LittleJ
  0 siblings, 1 reply; 7+ messages in thread
From: Chandra Seetharaman @ 2008-01-29 18:57 UTC (permalink / raw)
  To: device-mapper development

Hi,

Do you use LVM in this machine ? If yes, that would clarify why dm-0
thru dm-5 is used.

Can you send the o/p of "dmsetup ls" and "dmsetup table".

regards,

chandra
On Tue, 2008-01-29 at 12:17 -0500, LittleJ@AE.com wrote:
> I am not specifically blacklisting the /dev/dm-X devices.  The
> 5 /dev/dm-X devices on my system correspond to the 5 device special
> files in /dev/mapper on the second LUN that dm-multipath is currently
> managing.
> 
>  
> 
> [root@svwdcvispay01 ~]# cd /dev/mapper
> 
> [root@svwdcvispay01 mapper]# ls -la
> 
> total 0
> 
> drwxr-xr-x  2 root root     160 Jan 29 11:47 .
> 
> drwxr-xr-x  9 root root    4900 Jan 29 11:44 ..
> 
> crw-------  1 root root  10, 63 Jan 29 11:44 control
> 
> brw-rw----  1 root disk 253,  0 Jan 29 11:44 mpath1
> 
> brw-rw----  1 root disk 253,  1 Jan 29 11:44 mpath1p1
> 
> brw-rw----  1 root disk 253,  2 Jan 29 11:44 mpath1p2
> 
> brw-rw----  1 root disk 253,  3 Jan 29 11:44 mpath1p3
> 
> brw-rw----  1 root disk 253,  4 Jan 29 11:44 mpath1p5
> 
> [root@svwdcvispay01 mapper]# ls -la /dev/dm*
> 
> brw-r-----  1 root root 253, 0 Jan 29 11:44 /dev/dm-0
> 
> brw-r-----  1 root root 253, 1 Jan 29 11:44 /dev/dm-1
> 
> brw-r-----  1 root root 253, 2 Jan 29 11:44 /dev/dm-2
> 
> brw-r-----  1 root root 253, 3 Jan 29 11:44 /dev/dm-3
> 
> brw-r-----  1 root root 253, 4 Jan 29 11:44 /dev/dm-4
> 
> [root@svwdcvispay01 mapper]#
> 
>  
> 
> I believe that dm-multipath is internally blacklisting those devices.
> Notice if I execute `dmsetup remove_all` which removes all
> the /dev/mapper/mpath1* files and then recreate them that dm-multipath
> creates 5 new /dev/dm-* files:
> 
>  
> 
> [root@svwdcvispay01 mapper]# dmsetup remove_all
> 
> [root@svwdcvispay01 mapper]# ls -la
> 
> total 0
> 
> drwxr-xr-x  2 root root     60 Jan 29 12:09 .
> 
> drwxr-xr-x  9 root root   4900 Jan 29 11:44 ..
> 
> crw-------  1 root root 10, 63 Jan 29 11:44 control
> 
>  
> 
> [root@svwdcvispay01 mapper]# ls -la /dev/dm*
> 
> brw-r-----  1 root root 253, 0 Jan 29 11:44 /dev/dm-0
> 
> brw-r-----  1 root root 253, 1 Jan 29 11:44 /dev/dm-1
> 
> brw-r-----  1 root root 253, 2 Jan 29 11:44 /dev/dm-2
> 
> brw-r-----  1 root root 253, 3 Jan 29 11:44 /dev/dm-3
> 
> brw-r-----  1 root root 253, 4 Jan 29 11:44 /dev/dm-4
> 
>  
> 
> [root@svwdcvispay01 mapper]# multipath
> 
> create: mpath1 (36005076801810085c8000000000001a2)
> 
> [size=50 GB][features="1 queue_if_no_path"][hwhandler="0"]
> 
> \_ round-robin 0 [prio=50]
> 
>  \_ 1:0:1:1 sdd 8:48 [ready]
> 
> \_ round-robin 0 [prio=10]
> 
>  \_ 1:0:0:1 sdb 8:16 [ready]
> 
>  
> 
> [root@svwdcvispay01 mapper]# ls -la
> 
> total 0
> 
> drwxr-xr-x  2 root root     160 Jan 29 12:09 .
> 
> drwxr-xr-x  9 root root    5000 Jan 29 12:09 ..
> 
> crw-------  1 root root  10, 63 Jan 29 11:44 control
> 
> brw-rw----  1 root disk 253,  5 Jan 29 12:09 mpath1
> 
> brw-rw----  1 root disk 253,  6 Jan 29 12:09 mpath1p1
> 
> brw-rw----  1 root disk 253,  7 Jan 29 12:09 mpath1p2
> 
> brw-rw----  1 root disk 253,  8 Jan 29 12:09 mpath1p3
> 
> brw-rw----  1 root disk 253,  9 Jan 29 12:09 mpath1p5
> 
>  
> 
> [root@svwdcvispay01 mapper]# ls -la /dev/dm*
> 
> brw-r-----  1 root root 253, 0 Jan 29 11:44 /dev/dm-0
> 
> brw-r-----  1 root root 253, 1 Jan 29 11:44 /dev/dm-1
> 
> brw-r-----  1 root root 253, 2 Jan 29 11:44 /dev/dm-2
> 
> brw-r-----  1 root root 253, 3 Jan 29 11:44 /dev/dm-3
> 
> brw-r-----  1 root root 253, 4 Jan 29 11:44 /dev/dm-4
> 
> brw-r-----  1 root root 253, 5 Jan 29 12:09 /dev/dm-5
> 
> brw-r-----  1 root root 253, 6 Jan 29 12:09 /dev/dm-6
> 
> brw-r-----  1 root root 253, 7 Jan 29 12:09 /dev/dm-7
> 
> brw-r-----  1 root root 253, 8 Jan 29 12:09 /dev/dm-8
> 
> brw-r-----  1 root root 253, 9 Jan 29 12:09 /dev/dm-9
> 
> [root@svwdcvispay01 mapper]# 
> 
>  
> 
> Notice also that the blacklist has been automatically extended to
> cover the 5 new /dev/dm-X devices:
> 
>  
> 
> [root@svwdcvispay01 mapper]# multipath -v3 | more
> 
> load path identifiers cache
> 
> #
> 
> # all paths in cache :
> 
> #
> 
> 36005076801810085c800000000000194  1:0:0:0 sda 8:0   IBM     /2145
> 
> 36005076801810085c8000000000001a2  1:0:0:1 sdb 8:16 10 [active]
> IBM     /2145
> 
> 36005076801810085c800000000000194  1:0:1:0 sdc 8:32   IBM     /2145
> 
> 36005076801810085c8000000000001a2  1:0:1:1 sdd 8:48 50 [active]
> IBM     /2145
> 
> dm-0 blacklisted
> 
> dm-1 blacklisted
> 
> dm-2 blacklisted
> 
> dm-3 blacklisted
> 
> dm-4 blacklisted
> 
> dm-5 blacklisted
> 
> dm-6 blacklisted
> 
> dm-7 blacklisted
> 
> dm-8 blacklisted
> 
> dm-9 blacklisted
> 
> …
> 
>  
> 
> When I reboot the server dm-5 through dm-9 are gone and it is again
> using dm-0 through dm-4.
> 
>  
> 
> Joe Little
> 
> littlej@ae.com
> 
>  
> 
>  
> 
>  
> 
>  
> 
>                                    
> ______________________________________________________________________
> 
> From:dm-devel-bounces@redhat.com [mailto:dm-devel-bounces@redhat.com]
> On Behalf Of Gerald Nowitzky
> Sent: Tuesday, January 29, 2008 11:59 AM
> To: device-mapper development
> Subject: Re: [dm-devel] Problem using dm-multipath on first of 2 LUNs
> on system
> 
> 
>  
> 
> try and remove dm-0 to dm-4 from the blacklist. The devices
> in /dev/mapper are links to /dev/dm-x
> 
> 
> (Gerald)
> 
> 
>         ----- Original Message ----- 
>         
>         
>         From: LittleJ@AE.com 
>         
>         
>         To: dm-devel@redhat.com 
>         
>         
>         Sent: Tuesday, January 29, 2008 4:42 PM
>         
>         
>         Subject: [dm-devel] Problem using dm-multipath on first of 2
>         LUNs on system
>         
>         
>          
>         
>         
>         I am attempting to implement dm-multipath on a RHEL4U6 server
>         and I have been successful in enabling it on the second of 2
>         LUNs on the server but for whatever reason it will not create
>         the device special files in /dev/mapper for the fist LUN.
>         `multipath –d` shows that it identifies the first LUN and
>         wants to create the mpath0 files:
>         
>          
>         
>         [root@svwdcvispay01 etc]# multipath -d
>         
>         create: mpath0 (36005076801810085c800000000000194)
>         
>         [size=12 GB][features="1 queue_if_no_path"][hwhandler="0"]
>         
>         \_ round-robin 0 [prio=50]
>         
>          \_ 1:0:0:0 sda 8:0  [ready]
>         
>         \_ round-robin 0 [prio=10]
>         
>          \_ 1:0:1:0 sdc 8:32 [ready]
>         
>          
>         
>         switchpg: mpath1 (36005076801810085c8000000000001a2)
>         
>         [size=50 GB][features="1 queue_if_no_path"][hwhandler="0"]
>         
>         \_ round-robin 0 [prio=50]
>         
>          \_ 1:0:1:1 sdd 8:48 [active][ready]
>         
>         \_ round-robin 0 [prio=10]
>         
>          \_ 1:0:0:1 sdb 8:16 [active][ready]
>         
>          
>         
>         [root@svwdcvispay01 etc]#
>         
>          
>         
>          
>         
>         However `multipath –v3` generates a “set ACT_CREATE: map does
>         not exists” error in the mpath0 section:
>         
>          
>         
>         [root@svwdcvispay01 etc]# multipath -v3
>         
>         load path identifiers cache
>         
>         #
>         
>         # all paths in cache :
>         
>         #
>         
>         36005076801810085c800000000000194  1:0:0:0 sda 8:0
>         IBM     /2145
>         
>         36005076801810085c8000000000001a2  1:0:0:1 sdb 8:16 10
>         [active] IBM     /2145
>         
>         36005076801810085c800000000000194  1:0:1:0 sdc 8:32
>         IBM     /2145
>         
>         36005076801810085c8000000000001a2  1:0:1:1 sdd 8:48 50
>         [active] IBM     /2145
>         
>         dm-0 blacklisted
>         
>         dm-1 blacklisted
>         
>         dm-2 blacklisted
>         
>         dm-3 blacklisted
>         
>         dm-4 blacklisted
>         
>         md0 blacklisted
>         
>         ram0 blacklisted
>         
>         ram10 blacklisted
>         
>         ram11 blacklisted
>         
>         ram12 blacklisted
>         
>         ram13 blacklisted
>         
>         ram14 blacklisted
>         
>         ram15 blacklisted
>         
>         ram1 blacklisted
>         
>         ram2 blacklisted
>         
>         ram3 blacklisted
>         
>         ram4 blacklisted
>         
>         ram5 blacklisted
>         
>         ram6 blacklisted
>         
>         ram7 blacklisted
>         
>         ram8 blacklisted
>         
>         ram9 blacklisted
>         
>         ===== path info sda (mask 0x1f) =====
>         
>         bus = 1
>         
>         dev_t = 8:0
>         
>         size = 25165824
>         
>         vendor = IBM
>         
>         product = 2145
>         
>         rev = 0000
>         
>         h:b:t:l = 1:0:0:0
>         
>         tgt_node_name = 0x50050768010010b9
>         
>         serial = 020060402172XX00
>         
>         path checker = tur (controler setting)
>         
>         state = 2
>         
>         getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)
>         
>         prio = 50
>         
>         uid = 36005076801810085c800000000000194 (cache)
>         
>         ===== path info sdb (mask 0x1f) =====
>         
>         bus = 1
>         
>         dev_t = 8:16
>         
>         size = 104857600
>         
>         vendor = IBM
>         
>         product = 2145
>         
>         rev = 0000
>         
>         h:b:t:l = 1:0:0:1
>         
>         tgt_node_name = 0x50050768010010b9
>         
>         serial = 020060402172XX00
>         
>         path checker = tur (controler setting)
>         
>         state = 2
>         
>         getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)
>         
>         prio = 10
>         
>         uid = 36005076801810085c8000000000001a2 (cache)
>         
>         ===== path info sdc (mask 0x1f) =====
>         
>         bus = 1
>         
>         dev_t = 8:32
>         
>         size = 25165824
>         
>         vendor = IBM
>         
>         product = 2145
>         
>         rev = 0000
>         
>         h:b:t:l = 1:0:1:0
>         
>         tgt_node_name = 0x5005076801001082
>         
>         serial = 020060402172XX00
>         
>         path checker = tur (controler setting)
>         
>         state = 2
>         
>         getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)
>         
>         prio = 10
>         
>         uid = 36005076801810085c800000000000194 (cache)
>         
>         ===== path info sdd (mask 0x1f) =====
>         
>         bus = 1
>         
>         dev_t = 8:48
>         
>         size = 104857600
>         
>         vendor = IBM
>         
>         product = 2145
>         
>         rev = 0000
>         
>         h:b:t:l = 1:0:1:1
>         
>         tgt_node_name = 0x5005076801001082
>         
>         serial = 020060402172XX00
>         
>         path checker = tur (controler setting)
>         
>         state = 2
>         
>         getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)
>         
>         prio = 50
>         
>         uid = 36005076801810085c8000000000001a2 (cache)
>         
>         #
>         
>         # all paths :
>         
>         #
>         
>         36005076801810085c800000000000194  1:0:0:0 sda 8:0 50 [ready]
>         IBM     /2145
>         
>         36005076801810085c8000000000001a2  1:0:0:1 sdb 8:16 10
>         [active][ready] IBM
>         
>         36005076801810085c800000000000194  1:0:1:0 sdc 8:32 10 [ready]
>         IBM     /2145
>         
>         36005076801810085c8000000000001a2  1:0:1:1 sdd 8:48 50
>         [active][ready] IBM
>         
>         params = 1 queue_if_no_path 0 2 1 round-robin 0 1 1 8:48 1000
>         round-robin 0 1 1 8:16 1000
>         
>         status = 1 0 0 2 1 A 0 1 0 8:48 A 0 E 0 1 0 8:16 A 0
>         
>         Found matching wwid [36005076801810085c800000000000194] in
>         bindings file.
>         
>         Setting alias to mpath0
>         
>         pgpolicy = group_by_prio (controler setting)
>         
>         selector = round-robin 0 (internal default)
>         
>         features = 1 queue_if_no_path (controler setting)
>         
>         hwhandler = 0 (controler setting)
>         
>         rr_weight = 1 (internal default)
>         
>         rr_min_io = 1000 (config file default)
>         
>         no_path_retry = NONE (internal default)
>         
>         pg_timeout = NONE (internal default)
>         
>         0 25165824 multipath 1 queue_if_no_path 0 2 1 round-robin 0 1
>         1 8:0 1000 round-robin 0 1 1 8:32 1000
>         
>         set ACT_CREATE: map does not exists
>         
>         Found matching wwid [36005076801810085c8000000000001a2] in
>         bindings file.
>         
>         Setting alias to mpath1
>         
>         pgpolicy = group_by_prio (controler setting)
>         
>         selector = round-robin 0 (internal default)
>         
>         features = 1 queue_if_no_path (controler setting)
>         
>         hwhandler = 0 (controler setting)
>         
>         rr_weight = 1 (internal default)
>         
>         rr_min_io = 1000 (config file default)
>         
>         no_path_retry = NONE (internal default)
>         
>         pg_timeout = NONE (internal default)
>         
>         0 104857600 multipath 1 queue_if_no_path 0 2 1 round-robin 0 1
>         1 8:48 1000 round-robin 0 1 1 8:16 1000
>         
>         set ACT_NOTHING: map unchanged
>         
>         [root@svwdcvispay01 etc]#
>         
>          
>         
>          
>         
>         And notice that no /dev/mapper/mpath0 device special files
>         were created:
>         
>          
>         
>         [root@svwdcvispay01 etc]# ls -la /dev/mapper
>         
>         total 0
>         
>         drwxr-xr-x  2 root root     160 Jan 29 09:53 .
>         
>         drwxr-xr-x  9 root root    4900 Jan 29 09:51 ..
>         
>         crw-------  1 root root  10, 63 Jan 21 16:15 control
>         
>         brw-rw----  1 root disk 253,  0 Jan 21 16:15 mpath1
>         
>         brw-rw----  1 root disk 253,  1 Jan 21 16:15 mpath1p1
>         
>         brw-rw----  1 root disk 253,  2 Jan 21 16:15 mpath1p2
>         
>         brw-rw----  1 root disk 253,  3 Jan 21 16:15 mpath1p3
>         
>         brw-rw----  1 root disk 253,  4 Jan 21 16:15 mpath1p5
>         
>         [root@svwdcvispay01 etc]#
>         
>          
>         
>         My /etc/multipath.conf file is basic but I have tried creating an alias entry that looks like “multipaths {multipath {wwid   36005076801810085c800000000000194 alias os}}” for the first LUN but the results are the same, it still won’t create any device special files for the first LUN.
>         
>          
>         
>         [root@svwdcvispay01 mapper]# cat /etc/multipath.conf | grep -v
>         "#"
>         
>          
>         
>         defaults {
>         
>                 user_friendly_names yes
>         
>         }
>         
>          
>         
>         [root@svwdcvispay01 mapper]#
>         
>          
>         
>         I have been working this issue for over a week with IBM and
>         RedHat tech support and they have been unhelpful.  I need to
>         get this functional because the server in question has been
>         unstable using a single path to the SAN due to stability
>         issues we have had periodically with one of the SAN Volume
>         Controllers.  If additional information is needed to
>         troubleshoot this please let me know.
>         
>          
>         
>         Joe little
>         
>         littlej@ae.com
>         
>          
>         
>                                        
>         ______________________________________________________________
>         
>         --
>         dm-devel mailing list
>         dm-devel@redhat.com
>         https://www.redhat.com/mailman/listinfo/dm-devel
>         
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel
-- 

----------------------------------------------------------------------
    Chandra Seetharaman               | Be careful what you choose....
              - sekharan@us.ibm.com   |      .......you may get it.
----------------------------------------------------------------------

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: Problem using dm-multipath on first of 2 LUNs on system
  2008-01-29 15:42 Problem using dm-multipath on first of 2 LUNs on system LittleJ
  2008-01-29 16:58 ` Gerald Nowitzky
@ 2008-01-29 19:58 ` malahal
  2008-01-29 21:40   ` LittleJ
  1 sibling, 1 reply; 7+ messages in thread
From: malahal @ 2008-01-29 19:58 UTC (permalink / raw)
  To: dm-devel

LittleJ@AE.com [LittleJ@AE.com] wrote:
>    I am attempting to implement dm-multipath on a RHEL4U6 server and I have
>    been successful in enabling it on the second of 2 LUNs on the server but
>    for whatever reason it will not create the device special files in
>    /dev/mapper for the fist LUN.  `multipath -d` shows that it identifies the
>    first LUN and wants to create the mpath0 files:
> 
> 
> 
>    [root@svwdcvispay01 etc]# multipath -d
> 
>    create: mpath0 (36005076801810085c800000000000194)
> 
>    [size=12 GB][features="1 queue_if_no_path"][hwhandler="0"]
> 
>    \_ round-robin 0 [prio=50]
> 
>     \_ 1:0:0:0 sda 8:0  [ready]
> 
>    \_ round-robin 0 [prio=10]
> 
>     \_ 1:0:1:0 sdc 8:32 [ready]

One of the fields (DM path state) is missing from the above output.
Looks like it failed to create mpath0 properly. Make sure you enable
'syslog' and send out the syslog out when you run "multipath -v3" 

Also, can you do read/write I/O to sda and sdc devices? Try reading
data from both of those devices using dd or something similar. The
following should do:

dd if=/dev/sda of=/dev/null count=10
dd if=/dev/sdc of=/dev/null count=10

Thanks, Malahal.

^ permalink raw reply	[flat|nested] 7+ messages in thread

* RE: Problem using dm-multipath on first of 2 LUNs on system
  2008-01-29 18:57     ` Chandra Seetharaman
@ 2008-01-29 21:24       ` LittleJ
  0 siblings, 0 replies; 7+ messages in thread
From: LittleJ @ 2008-01-29 21:24 UTC (permalink / raw)
  To: sekharan, dm-devel

I am not using LVM on the system:

[root@svwdcvispay01 ~]# vgdisplay
  No volume groups found
[root@svwdcvispay01 ~]#

The output of the 2 commands you requested:

[root@svwdcvispay01 ~]# dmsetup ls
mpath1  (253, 0)
mpath1p5        (253, 4)
mpath1p3        (253, 3)
mpath1p2        (253, 2)
mpath1p1        (253, 1)
[root@svwdcvispay01 ~]# dmsetup table
mpath1: 0 104857600 multipath 1 queue_if_no_path 0 2 1 round-robin 0 1 1
8:48 1000 round-robin 0 1 1 8:16 1000
mpath1p5: 0 55697292 linear 253:0 49158963
mpath1p3: 0 8193150 linear 253:0 40965750
mpath1p2: 0 20482875 linear 253:0 20482875
mpath1p1: 0 20482812 linear 253:0 63
[root@svwdcvispay01 ~]#

Unfortunately the above commands only seem to be referencing the mpath1
LUN and make no mention of the first LUN (mpath0).  I hope this helps.

Joe Little
littlej@ae.com




-----Original Message-----
From: dm-devel-bounces@redhat.com [mailto:dm-devel-bounces@redhat.com]
On Behalf Of Chandra Seetharaman
Sent: Tuesday, January 29, 2008 1:57 PM
To: device-mapper development
Subject: RE: [dm-devel] Problem using dm-multipath on first of 2 LUNs on
system

Hi,

Do you use LVM in this machine ? If yes, that would clarify why dm-0
thru dm-5 is used.

Can you send the o/p of "dmsetup ls" and "dmsetup table".

regards,

chandra
On Tue, 2008-01-29 at 12:17 -0500, LittleJ@AE.com wrote:
> I am not specifically blacklisting the /dev/dm-X devices.  The
> 5 /dev/dm-X devices on my system correspond to the 5 device special
> files in /dev/mapper on the second LUN that dm-multipath is currently
> managing.
> 
>  
> 
> [root@svwdcvispay01 ~]# cd /dev/mapper
> 
> [root@svwdcvispay01 mapper]# ls -la
> 
> total 0
> 
> drwxr-xr-x  2 root root     160 Jan 29 11:47 .
> 
> drwxr-xr-x  9 root root    4900 Jan 29 11:44 ..
> 
> crw-------  1 root root  10, 63 Jan 29 11:44 control
> 
> brw-rw----  1 root disk 253,  0 Jan 29 11:44 mpath1
> 
> brw-rw----  1 root disk 253,  1 Jan 29 11:44 mpath1p1
> 
> brw-rw----  1 root disk 253,  2 Jan 29 11:44 mpath1p2
> 
> brw-rw----  1 root disk 253,  3 Jan 29 11:44 mpath1p3
> 
> brw-rw----  1 root disk 253,  4 Jan 29 11:44 mpath1p5
> 
> [root@svwdcvispay01 mapper]# ls -la /dev/dm*
> 
> brw-r-----  1 root root 253, 0 Jan 29 11:44 /dev/dm-0
> 
> brw-r-----  1 root root 253, 1 Jan 29 11:44 /dev/dm-1
> 
> brw-r-----  1 root root 253, 2 Jan 29 11:44 /dev/dm-2
> 
> brw-r-----  1 root root 253, 3 Jan 29 11:44 /dev/dm-3
> 
> brw-r-----  1 root root 253, 4 Jan 29 11:44 /dev/dm-4
> 
> [root@svwdcvispay01 mapper]#
> 
>  
> 
> I believe that dm-multipath is internally blacklisting those devices.
> Notice if I execute `dmsetup remove_all` which removes all
> the /dev/mapper/mpath1* files and then recreate them that dm-multipath
> creates 5 new /dev/dm-* files:
> 
>  
> 
> [root@svwdcvispay01 mapper]# dmsetup remove_all
> 
> [root@svwdcvispay01 mapper]# ls -la
> 
> total 0
> 
> drwxr-xr-x  2 root root     60 Jan 29 12:09 .
> 
> drwxr-xr-x  9 root root   4900 Jan 29 11:44 ..
> 
> crw-------  1 root root 10, 63 Jan 29 11:44 control
> 
>  
> 
> [root@svwdcvispay01 mapper]# ls -la /dev/dm*
> 
> brw-r-----  1 root root 253, 0 Jan 29 11:44 /dev/dm-0
> 
> brw-r-----  1 root root 253, 1 Jan 29 11:44 /dev/dm-1
> 
> brw-r-----  1 root root 253, 2 Jan 29 11:44 /dev/dm-2
> 
> brw-r-----  1 root root 253, 3 Jan 29 11:44 /dev/dm-3
> 
> brw-r-----  1 root root 253, 4 Jan 29 11:44 /dev/dm-4
> 
>  
> 
> [root@svwdcvispay01 mapper]# multipath
> 
> create: mpath1 (36005076801810085c8000000000001a2)
> 
> [size=50 GB][features="1 queue_if_no_path"][hwhandler="0"]
> 
> \_ round-robin 0 [prio=50]
> 
>  \_ 1:0:1:1 sdd 8:48 [ready]
> 
> \_ round-robin 0 [prio=10]
> 
>  \_ 1:0:0:1 sdb 8:16 [ready]
> 
>  
> 
> [root@svwdcvispay01 mapper]# ls -la
> 
> total 0
> 
> drwxr-xr-x  2 root root     160 Jan 29 12:09 .
> 
> drwxr-xr-x  9 root root    5000 Jan 29 12:09 ..
> 
> crw-------  1 root root  10, 63 Jan 29 11:44 control
> 
> brw-rw----  1 root disk 253,  5 Jan 29 12:09 mpath1
> 
> brw-rw----  1 root disk 253,  6 Jan 29 12:09 mpath1p1
> 
> brw-rw----  1 root disk 253,  7 Jan 29 12:09 mpath1p2
> 
> brw-rw----  1 root disk 253,  8 Jan 29 12:09 mpath1p3
> 
> brw-rw----  1 root disk 253,  9 Jan 29 12:09 mpath1p5
> 
>  
> 
> [root@svwdcvispay01 mapper]# ls -la /dev/dm*
> 
> brw-r-----  1 root root 253, 0 Jan 29 11:44 /dev/dm-0
> 
> brw-r-----  1 root root 253, 1 Jan 29 11:44 /dev/dm-1
> 
> brw-r-----  1 root root 253, 2 Jan 29 11:44 /dev/dm-2
> 
> brw-r-----  1 root root 253, 3 Jan 29 11:44 /dev/dm-3
> 
> brw-r-----  1 root root 253, 4 Jan 29 11:44 /dev/dm-4
> 
> brw-r-----  1 root root 253, 5 Jan 29 12:09 /dev/dm-5
> 
> brw-r-----  1 root root 253, 6 Jan 29 12:09 /dev/dm-6
> 
> brw-r-----  1 root root 253, 7 Jan 29 12:09 /dev/dm-7
> 
> brw-r-----  1 root root 253, 8 Jan 29 12:09 /dev/dm-8
> 
> brw-r-----  1 root root 253, 9 Jan 29 12:09 /dev/dm-9
> 
> [root@svwdcvispay01 mapper]# 
> 
>  
> 
> Notice also that the blacklist has been automatically extended to
> cover the 5 new /dev/dm-X devices:
> 
>  
> 
> [root@svwdcvispay01 mapper]# multipath -v3 | more
> 
> load path identifiers cache
> 
> #
> 
> # all paths in cache :
> 
> #
> 
> 36005076801810085c800000000000194  1:0:0:0 sda 8:0   IBM     /2145
> 
> 36005076801810085c8000000000001a2  1:0:0:1 sdb 8:16 10 [active]
> IBM     /2145
> 
> 36005076801810085c800000000000194  1:0:1:0 sdc 8:32   IBM     /2145
> 
> 36005076801810085c8000000000001a2  1:0:1:1 sdd 8:48 50 [active]
> IBM     /2145
> 
> dm-0 blacklisted
> 
> dm-1 blacklisted
> 
> dm-2 blacklisted
> 
> dm-3 blacklisted
> 
> dm-4 blacklisted
> 
> dm-5 blacklisted
> 
> dm-6 blacklisted
> 
> dm-7 blacklisted
> 
> dm-8 blacklisted
> 
> dm-9 blacklisted
> 
> ...
> 
>  
> 
> When I reboot the server dm-5 through dm-9 are gone and it is again
> using dm-0 through dm-4.
> 
>  
> 
> Joe Little
> 
> littlej@ae.com
> 
>  
> 
>  
> 
>  
> 
>  
> 
>                                    
> ______________________________________________________________________
> 
> From:dm-devel-bounces@redhat.com [mailto:dm-devel-bounces@redhat.com]
> On Behalf Of Gerald Nowitzky
> Sent: Tuesday, January 29, 2008 11:59 AM
> To: device-mapper development
> Subject: Re: [dm-devel] Problem using dm-multipath on first of 2 LUNs
> on system
> 
> 
>  
> 
> try and remove dm-0 to dm-4 from the blacklist. The devices
> in /dev/mapper are links to /dev/dm-x
> 
> 
> (Gerald)
> 
> 
>         ----- Original Message ----- 
>         
>         
>         From: LittleJ@AE.com 
>         
>         
>         To: dm-devel@redhat.com 
>         
>         
>         Sent: Tuesday, January 29, 2008 4:42 PM
>         
>         
>         Subject: [dm-devel] Problem using dm-multipath on first of 2
>         LUNs on system
>         
>         
>          
>         
>         
>         I am attempting to implement dm-multipath on a RHEL4U6 server
>         and I have been successful in enabling it on the second of 2
>         LUNs on the server but for whatever reason it will not create
>         the device special files in /dev/mapper for the fist LUN.
>         `multipath -d` shows that it identifies the first LUN and
>         wants to create the mpath0 files:
>         
>          
>         
>         [root@svwdcvispay01 etc]# multipath -d
>         
>         create: mpath0 (36005076801810085c800000000000194)
>         
>         [size=12 GB][features="1 queue_if_no_path"][hwhandler="0"]
>         
>         \_ round-robin 0 [prio=50]
>         
>          \_ 1:0:0:0 sda 8:0  [ready]
>         
>         \_ round-robin 0 [prio=10]
>         
>          \_ 1:0:1:0 sdc 8:32 [ready]
>         
>          
>         
>         switchpg: mpath1 (36005076801810085c8000000000001a2)
>         
>         [size=50 GB][features="1 queue_if_no_path"][hwhandler="0"]
>         
>         \_ round-robin 0 [prio=50]
>         
>          \_ 1:0:1:1 sdd 8:48 [active][ready]
>         
>         \_ round-robin 0 [prio=10]
>         
>          \_ 1:0:0:1 sdb 8:16 [active][ready]
>         
>          
>         
>         [root@svwdcvispay01 etc]#
>         
>          
>         
>          
>         
>         However `multipath -v3` generates a "set ACT_CREATE: map does
>         not exists" error in the mpath0 section:
>         
>          
>         
>         [root@svwdcvispay01 etc]# multipath -v3
>         
>         load path identifiers cache
>         
>         #
>         
>         # all paths in cache :
>         
>         #
>         
>         36005076801810085c800000000000194  1:0:0:0 sda 8:0
>         IBM     /2145
>         
>         36005076801810085c8000000000001a2  1:0:0:1 sdb 8:16 10
>         [active] IBM     /2145
>         
>         36005076801810085c800000000000194  1:0:1:0 sdc 8:32
>         IBM     /2145
>         
>         36005076801810085c8000000000001a2  1:0:1:1 sdd 8:48 50
>         [active] IBM     /2145
>         
>         dm-0 blacklisted
>         
>         dm-1 blacklisted
>         
>         dm-2 blacklisted
>         
>         dm-3 blacklisted
>         
>         dm-4 blacklisted
>         
>         md0 blacklisted
>         
>         ram0 blacklisted
>         
>         ram10 blacklisted
>         
>         ram11 blacklisted
>         
>         ram12 blacklisted
>         
>         ram13 blacklisted
>         
>         ram14 blacklisted
>         
>         ram15 blacklisted
>         
>         ram1 blacklisted
>         
>         ram2 blacklisted
>         
>         ram3 blacklisted
>         
>         ram4 blacklisted
>         
>         ram5 blacklisted
>         
>         ram6 blacklisted
>         
>         ram7 blacklisted
>         
>         ram8 blacklisted
>         
>         ram9 blacklisted
>         
>         ===== path info sda (mask 0x1f) =====
>         
>         bus = 1
>         
>         dev_t = 8:0
>         
>         size = 25165824
>         
>         vendor = IBM
>         
>         product = 2145
>         
>         rev = 0000
>         
>         h:b:t:l = 1:0:0:0
>         
>         tgt_node_name = 0x50050768010010b9
>         
>         serial = 020060402172XX00
>         
>         path checker = tur (controler setting)
>         
>         state = 2
>         
>         getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)
>         
>         prio = 50
>         
>         uid = 36005076801810085c800000000000194 (cache)
>         
>         ===== path info sdb (mask 0x1f) =====
>         
>         bus = 1
>         
>         dev_t = 8:16
>         
>         size = 104857600
>         
>         vendor = IBM
>         
>         product = 2145
>         
>         rev = 0000
>         
>         h:b:t:l = 1:0:0:1
>         
>         tgt_node_name = 0x50050768010010b9
>         
>         serial = 020060402172XX00
>         
>         path checker = tur (controler setting)
>         
>         state = 2
>         
>         getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)
>         
>         prio = 10
>         
>         uid = 36005076801810085c8000000000001a2 (cache)
>         
>         ===== path info sdc (mask 0x1f) =====
>         
>         bus = 1
>         
>         dev_t = 8:32
>         
>         size = 25165824
>         
>         vendor = IBM
>         
>         product = 2145
>         
>         rev = 0000
>         
>         h:b:t:l = 1:0:1:0
>         
>         tgt_node_name = 0x5005076801001082
>         
>         serial = 020060402172XX00
>         
>         path checker = tur (controler setting)
>         
>         state = 2
>         
>         getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)
>         
>         prio = 10
>         
>         uid = 36005076801810085c800000000000194 (cache)
>         
>         ===== path info sdd (mask 0x1f) =====
>         
>         bus = 1
>         
>         dev_t = 8:48
>         
>         size = 104857600
>         
>         vendor = IBM
>         
>         product = 2145
>         
>         rev = 0000
>         
>         h:b:t:l = 1:0:1:1
>         
>         tgt_node_name = 0x5005076801001082
>         
>         serial = 020060402172XX00
>         
>         path checker = tur (controler setting)
>         
>         state = 2
>         
>         getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)
>         
>         prio = 50
>         
>         uid = 36005076801810085c8000000000001a2 (cache)
>         
>         #
>         
>         # all paths :
>         
>         #
>         
>         36005076801810085c800000000000194  1:0:0:0 sda 8:0 50 [ready]
>         IBM     /2145
>         
>         36005076801810085c8000000000001a2  1:0:0:1 sdb 8:16 10
>         [active][ready] IBM
>         
>         36005076801810085c800000000000194  1:0:1:0 sdc 8:32 10 [ready]
>         IBM     /2145
>         
>         36005076801810085c8000000000001a2  1:0:1:1 sdd 8:48 50
>         [active][ready] IBM
>         
>         params = 1 queue_if_no_path 0 2 1 round-robin 0 1 1 8:48 1000
>         round-robin 0 1 1 8:16 1000
>         
>         status = 1 0 0 2 1 A 0 1 0 8:48 A 0 E 0 1 0 8:16 A 0
>         
>         Found matching wwid [36005076801810085c800000000000194] in
>         bindings file.
>         
>         Setting alias to mpath0
>         
>         pgpolicy = group_by_prio (controler setting)
>         
>         selector = round-robin 0 (internal default)
>         
>         features = 1 queue_if_no_path (controler setting)
>         
>         hwhandler = 0 (controler setting)
>         
>         rr_weight = 1 (internal default)
>         
>         rr_min_io = 1000 (config file default)
>         
>         no_path_retry = NONE (internal default)
>         
>         pg_timeout = NONE (internal default)
>         
>         0 25165824 multipath 1 queue_if_no_path 0 2 1 round-robin 0 1
>         1 8:0 1000 round-robin 0 1 1 8:32 1000
>         
>         set ACT_CREATE: map does not exists
>         
>         Found matching wwid [36005076801810085c8000000000001a2] in
>         bindings file.
>         
>         Setting alias to mpath1
>         
>         pgpolicy = group_by_prio (controler setting)
>         
>         selector = round-robin 0 (internal default)
>         
>         features = 1 queue_if_no_path (controler setting)
>         
>         hwhandler = 0 (controler setting)
>         
>         rr_weight = 1 (internal default)
>         
>         rr_min_io = 1000 (config file default)
>         
>         no_path_retry = NONE (internal default)
>         
>         pg_timeout = NONE (internal default)
>         
>         0 104857600 multipath 1 queue_if_no_path 0 2 1 round-robin 0 1
>         1 8:48 1000 round-robin 0 1 1 8:16 1000
>         
>         set ACT_NOTHING: map unchanged
>         
>         [root@svwdcvispay01 etc]#
>         
>          
>         
>          
>         
>         And notice that no /dev/mapper/mpath0 device special files
>         were created:
>         
>          
>         
>         [root@svwdcvispay01 etc]# ls -la /dev/mapper
>         
>         total 0
>         
>         drwxr-xr-x  2 root root     160 Jan 29 09:53 .
>         
>         drwxr-xr-x  9 root root    4900 Jan 29 09:51 ..
>         
>         crw-------  1 root root  10, 63 Jan 21 16:15 control
>         
>         brw-rw----  1 root disk 253,  0 Jan 21 16:15 mpath1
>         
>         brw-rw----  1 root disk 253,  1 Jan 21 16:15 mpath1p1
>         
>         brw-rw----  1 root disk 253,  2 Jan 21 16:15 mpath1p2
>         
>         brw-rw----  1 root disk 253,  3 Jan 21 16:15 mpath1p3
>         
>         brw-rw----  1 root disk 253,  4 Jan 21 16:15 mpath1p5
>         
>         [root@svwdcvispay01 etc]#
>         
>          
>         
>         My /etc/multipath.conf file is basic but I have tried creating
an alias entry that looks like "multipaths {multipath {wwid
36005076801810085c800000000000194 alias os}}" for the first LUN but the
results are the same, it still won't create any device special files for
the first LUN.
>         
>          
>         
>         [root@svwdcvispay01 mapper]# cat /etc/multipath.conf | grep -v
>         "#"
>         
>          
>         
>         defaults {
>         
>                 user_friendly_names yes
>         
>         }
>         
>          
>         
>         [root@svwdcvispay01 mapper]#
>         
>          
>         
>         I have been working this issue for over a week with IBM and
>         RedHat tech support and they have been unhelpful.  I need to
>         get this functional because the server in question has been
>         unstable using a single path to the SAN due to stability
>         issues we have had periodically with one of the SAN Volume
>         Controllers.  If additional information is needed to
>         troubleshoot this please let me know.
>         
>          
>         
>         Joe little
>         
>         littlej@ae.com
>         
>          
>         
>                                        
>         ______________________________________________________________
>         
>         --
>         dm-devel mailing list
>         dm-devel@redhat.com
>         https://www.redhat.com/mailman/listinfo/dm-devel
>         
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel
-- 

----------------------------------------------------------------------
    Chandra Seetharaman               | Be careful what you choose....
              - sekharan@us.ibm.com   |      .......you may get it.
----------------------------------------------------------------------


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^ permalink raw reply	[flat|nested] 7+ messages in thread

* RE: Problem using dm-multipath on first of 2 LUNs on system
  2008-01-29 19:58 ` malahal
@ 2008-01-29 21:40   ` LittleJ
  0 siblings, 0 replies; 7+ messages in thread
From: LittleJ @ 2008-01-29 21:40 UTC (permalink / raw)
  To: dm-devel


When I execute `multipath -v3` the following appears in
/var/log/messages:

Jan 29 16:32:50 svwdcvispay01 kernel: device-mapper: dm-multipath: error
getting device
Jan 29 16:32:50 svwdcvispay01 kernel: device-mapper: error adding target
to table
Jan 29 16:32:52 svwdcvispay01 hald[3620]: Timed out waiting for hotplug
event 361. Rebasing to 362
Jan 29 16:33:06 svwdcvispay01 hal.hotplug[22665]: timout(10000 ms)
waiting for /block/dm-5

I am able to perform I/O to both /dev/sda and /dev/sdc:

[root@svwdcvispay01 ~]# dd if=/dev/sda of=/dev/null count=10
10+0 records in
10+0 records out
[root@svwdcvispay01 ~]# dd if=/dev/sdc of=/dev/null count=10
10+0 records in
10+0 records out
[root@svwdcvispay01 ~]#

Joe Little
littlej@ae.com




-----Original Message-----
From: dm-devel-bounces@redhat.com [mailto:dm-devel-bounces@redhat.com]
On Behalf Of malahal@us.ibm.com
Sent: Tuesday, January 29, 2008 2:58 PM
To: dm-devel@redhat.com
Subject: Re: [dm-devel] Problem using dm-multipath on first of 2 LUNs on
system

LittleJ@AE.com [LittleJ@AE.com] wrote:
>    I am attempting to implement dm-multipath on a RHEL4U6 server and I
have
>    been successful in enabling it on the second of 2 LUNs on the
server but
>    for whatever reason it will not create the device special files in
>    /dev/mapper for the fist LUN.  `multipath -d` shows that it
identifies the
>    first LUN and wants to create the mpath0 files:
> 
> 
> 
>    [root@svwdcvispay01 etc]# multipath -d
> 
>    create: mpath0 (36005076801810085c800000000000194)
> 
>    [size=12 GB][features="1 queue_if_no_path"][hwhandler="0"]
> 
>    \_ round-robin 0 [prio=50]
> 
>     \_ 1:0:0:0 sda 8:0  [ready]
> 
>    \_ round-robin 0 [prio=10]
> 
>     \_ 1:0:1:0 sdc 8:32 [ready]

One of the fields (DM path state) is missing from the above output.
Looks like it failed to create mpath0 properly. Make sure you enable
'syslog' and send out the syslog out when you run "multipath -v3" 

Also, can you do read/write I/O to sda and sdc devices? Try reading
data from both of those devices using dd or something similar. The
following should do:

dd if=/dev/sda of=/dev/null count=10
dd if=/dev/sdc of=/dev/null count=10

Thanks, Malahal.

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^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2008-01-29 21:40 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-01-29 15:42 Problem using dm-multipath on first of 2 LUNs on system LittleJ
2008-01-29 16:58 ` Gerald Nowitzky
2008-01-29 17:17   ` LittleJ
2008-01-29 18:57     ` Chandra Seetharaman
2008-01-29 21:24       ` LittleJ
2008-01-29 19:58 ` malahal
2008-01-29 21:40   ` LittleJ

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