multipath-tools with STK FLEXLINE 380

multipath-tools with STK FLEXLINE 380

[Tony Lapointe]

Hi list,

we're trying to get multipath working on a server (which run SLES 10)
connected to a STK FLEXLINE 380 SAN. This SAN has AVT (Auto Volume
Transfer) activated and we have two LUNs exported to the server, which
one on a different preferred path (one on controller A and the other on
controller B).

Since the SAN has AVT activated and that we are using preferred path,
i'm guessing that we have to use group_by_prio policy with the
mpath_prio_tpc callout program.

I can see that mpath_prio_tpc get the right priority :

# mpath_prio_tpc /dev/sda
3
# mpath_prio_tpc /dev/sdb
0
# mpath_prio_tpc /dev/sdd
0
# mpath_prio_tpc /dev/sde
3

and then if i issue "fdisk -l" on /dev/sda and /dev/sde, each LUN stay
on his preferred controller on the SAN.

The problem is when i start multipath, it will not coalesces the paths
together.

Here's my multipath.conf :

defaults {
        udev_dir        /dev
        polling_interval 10


        path_grouping_policy    group_by_prio
        getuid_callout  "/sbin/scsi_id -g -u -s /block/%n"


        prio_callout    "/sbin/mpath_prio_tpc /dev/%n"
        path_checker    tur

        rr_weight       priorities

        failback        immediate

#       user_friendly_names yes

}
blacklist {
        devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
        devnode "^hd[a-z][[0-9]*]"
        devnode "^cciss!c[0-9]d[0-9]*[p[0-9]*]"
        device {
                vendor "STK"
                product "Universal Xport"
        }
}

multipaths {

        multipath {
                wwid                   3600a0b8000119c20000002a445338779
                alias                  test1
        }

        multipath {
                wwid                   3600a0b8000119c20000002a945338e7f
                alias                  test2
        }

}


and here's the relevant error part of the output of "multipath -v3" :

...
test1: set ACT_CREATE (map does not exist)
test1: domap (0) failure for create/reload map
...
test2: set ACT_CREATE (map does not exist)
test2: domap (0) failure for create/reload map
...


Am i missing something or multipath-tools just can't work on
STK FLEXLINE 380 with AVT enabled?


Thanks a lot for your time! 


-- 
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Re: multipath-tools with STK FLEXLINE 380

[Hannes Reinecke]

Tony Lapointe wrote:
> Hi list,
> 
> we're trying to get multipath working on a server (which run SLES 10)
> connected to a STK FLEXLINE 380 SAN. This SAN has AVT (Auto Volume
> Transfer) activated and we have two LUNs exported to the server, which
> one on a different preferred path (one on controller A and the other on
> controller B).
> 
> Since the SAN has AVT activated and that we are using preferred path,
> i'm guessing that we have to use group_by_prio policy with the
> mpath_prio_tpc callout program.
> 
> I can see that mpath_prio_tpc get the right priority :
> 
> # mpath_prio_tpc /dev/sda
> 3
> # mpath_prio_tpc /dev/sdb
> 0
> # mpath_prio_tpc /dev/sdd
> 0
> # mpath_prio_tpc /dev/sde
> 3
> 
> and then if i issue "fdisk -l" on /dev/sda and /dev/sde, each LUN stay
> on his preferred controller on the SAN.
> 
> The problem is when i start multipath, it will not coalesces the paths
> together.
> 
> Here's my multipath.conf :
> 
> defaults {
>         udev_dir        /dev
>         polling_interval 10
> 
> 
>         path_grouping_policy    group_by_prio
>         getuid_callout  "/sbin/scsi_id -g -u -s /block/%n"
> 
> 
>         prio_callout    "/sbin/mpath_prio_tpc /dev/%n"
>         path_checker    tur
> 
>         rr_weight       priorities
> 
>         failback        immediate
> 
> #       user_friendly_names yes
> 
> }
Do not use 'rr_weight=priorities'. The priorities handling is currently 
buggered; or, put it the other way round, you will need at least my 
latest fix to get it working. Just remove that line and stay with the 
defaults. That should work.

And as a sidenote: Using 'group_by_prio' and 'rr_weight=priorities' is 
completely pointless, even if 'rr_weight=priorities' should be working.
'group_by_prio' will lump all devices with the same priority into one 
group. And 'rr_weight=priorities' will then modify the 'minio' based on 
the priority. So you can as well directly modify the 'minio' parameter.
'rr_weight=priorities' only makes sense if you have path with different 
priorities in one group, ie when using 'multibus' or 'group_by_serial'.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke			hare@suse.de
SuSE Linux Products GmbH		S390 & zSeries
Maxfeldstraße 5				+49 911 74053 688
90409 Nürnberg				http://www.suse.de

Re: multipath-tools with STK FLEXLINE 380

[Tony Lapointe]

                Do not use 'rr_weight=priorities'. The priorities
                handling is currently buggered; or, put it the other way
                round, you will need at least my latest fix to get it
                working. Just remove that line and stay with the
                defaults. That should work.
                
                And as a sidenote: Using 'group_by_prio' and
                'rr_weight=priorities' is completely pointless, even if
                'rr_weight=priorities' should be working.'group_by_prio'
                will lump all devices with the same priority into one
                group. And 'rr_weight=priorities' will then modify the
                'minio' based on the priority. So you can as well
                directly modify the 'minio'
                parameter.'rr_weight=priorities' only makes sense if you
                have path with different priorities in one group, ie
                when using 'multibus' or 'group_by_serial'.
                Cheers,
                
                Hannes
                --
                Dr. Hannes Reinecke			hare suse de
                SuSE Linux Products GmbH		S390 & zSeries
                Maxfeldstraße 5				+49 911 74053 688
                90409 Nürnberg				http://www.suse.de




Hi Hannes,

thanks for the reply.

I've tried without "rr_weight=priorities" in my multipath.conf but it does not work either.
The only difference it makes is that "multipath -v3" now output : "rr_weight = 1 (internal default)"
instead of "rr_weight = 2 (config file default)".

I was thinking that "group_by_prio" is use to group together devices with differents
priorities, with the one with the highest priority first, is it wrong?

The output of "multipath -d -v2" seems to reflect this :

create: test1 (3600a0b8000119c20000002a445338779) STK,FLEXLINE 380
[size=100G][features=0][hwhandler=0]
\_ round-robin 0 [prio=3][undef]
 \_ 0:0:0:0 sda 8:0   [undef][ready]
\_ round-robin 0 [prio=0][undef]
 \_ 1:0:0:0 sdd 8:48  [undef][ready]
create: test2 (3600a0b8000119c20000002a945338e7f) STK,FLEXLINE 380
[size=100G][features=0][hwhandler=0]
\_ round-robin 0 [prio=3][undef]
 \_ 1:0:0:1 sde 8:64  [undef][ready]
\_ round-robin 0 [prio=0][undef]
 \_ 0:0:0:1 sdb 8:16  [undef][ready]
create: test1 (3600a0b8000119c20000002a445338779) STK,FLEXLINE 380
[size=100G][features=0][hwhandler=0]
\_ round-robin 0 [prio=3][undef]
 \_ 0:0:0:0 sda 8:0   [undef][ready]
\_ round-robin 0 [prio=0][undef]
 \_ 1:0:0:0 sdd 8:48  [undef][ready]
create: test2 (3600a0b8000119c20000002a945338e7f) STK,FLEXLINE 380
[size=100G][features=0][hwhandler=0]
\_ round-robin 0 [prio=3][undef]
 \_ 1:0:0:1 sde 8:64  [undef][ready]
\_ round-robin 0 [prio=0][undef]
 \_ 0:0:0:1 sdb 8:16  [undef][ready]


showing sda and sde (prio=3) always being first...

You're talking about your latest fix; is there a place where i can find new version of the
multipath-tools package for SLES 10?


Thanks again!


-- 
#################################################
#                                               #
# Tony Lapointe @ Connexim                      #
# Administrateur Systeme # System Administrator #
# RHCE # LPI                                    #
# phone -> 1-514-879-5951                       #
# page -> 1-514-851-2560                        #
# email -> tony.lapointe@connexim.ca            #
# epager -> 5148512560@pager.mobility.com       #
#                                               #
#################################################
#                                               #
# # mount --bind /bin/su /bin/login             #
#                                               #
#################################################

Re: multipath-tools with STK FLEXLINE 380

[Hannes Reinecke]

Tony Lapointe wrote:
>                 Do not use 'rr_weight=priorities'. The priorities
>                 handling is currently buggered; or, put it the other way
>                 round, you will need at least my latest fix to get it
>                 working. Just remove that line and stay with the
>                 defaults. That should work.
>                 
>                 And as a sidenote: Using 'group_by_prio' and
>                 'rr_weight=priorities' is completely pointless, even if
>                 'rr_weight=priorities' should be working.'group_by_prio'
>                 will lump all devices with the same priority into one
>                 group. And 'rr_weight=priorities' will then modify the
>                 'minio' based on the priority. So you can as well
>                 directly modify the 'minio'
>                 parameter.'rr_weight=priorities' only makes sense if you
>                 have path with different priorities in one group, ie
>                 when using 'multibus' or 'group_by_serial'.
>                 Cheers,
>                 
>                 Hannes
>                 --
>                 Dr. Hannes Reinecke			hare suse de
>                 SuSE Linux Products GmbH		S390 & zSeries
>                 Maxfeldstraße 5				+49 911 74053 688
>                 90409 Nürnberg				http://www.suse.de
> 
> 
> 
> 
> Hi Hannes,
> 
> thanks for the reply.
> 
> I've tried without "rr_weight=priorities" in my multipath.conf but  it does
 > not work either.
> The only difference it makes is that "multipath -v3" now output : 
 > "rr_weight = 1 (internal default)"
> instead of "rr_weight = 2 (config file default)".
> 
> I was thinking that "group_by_prio" is use to group together devices with
 > differents priorities, with the one with the highest priority first, 
is it wrong?
> 
Yes. It groups devices with _identical_ priorities together.

> The output of "multipath -d -v2" seems to reflect this :
> 
[ .. ]

The output is correct. You have two paths to each disk, and each path 
has a different priority. So the multipath topology is correct.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke			hare@suse.de
SuSE Linux Products GmbH		S390 & zSeries
Maxfeldstraße 5				+49 911 74053 688
90409 Nürnberg				http://www.suse.de