A path to a different device was added to an existing mapth

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* A path to a different device was added to an existing mapth
@ 2015-03-19 10:10 Ilan Steinberg
  2015-03-19 10:35 ` Ilan Steinberg
  0 siblings, 1 reply; 4+ messages in thread
From: Ilan Steinberg @ 2015-03-19 10:10 UTC (permalink / raw)
  To: dm-devel@redhat.com; +Cc: Guy Keren, Eli Malul, Shahar Salzman


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Hello,


I have never posted here before but I can across an interesting error.


I have run into a situation were a path (sdag) to LUN 15 with a scsi serial number of ending with 0xd5190010 was added to an mapth (mpathiw) which is for LUN 11 with scsi serial number ending with 0xd5190026 (sdz and sdw)


I would appreciate any help understanding how/why this happened.


Initiator Info:

Linux il-ksm3-044 2.6.32-431.el6.x86_64 #1

device-mapper-multipath version 0.4.9


multipath.conf:

defaults {
                   user_friendly_names     yes
                   polling_interval        10
                    verbosity               2
}
devices {
                    device  {
                             vendor                      "KMNRIO"
                             product                     "K2"
                         path_grouping_policy        multibus
                             getuid_callout          "/lib/udev/scsi_id --whitelisted --device=/dev/%n"
                             path_checker                tur
                             path_selector               "queue-length 0"
                             no_path_retry               fail
                             hardware_handler            "0"
                             rr_weight                   priorities
                             rr_min_io               1
                             failback                15
                             fast_io_fail_tmo        5
                             dev_loss_tmo            8
                             }
}


Since I see that sdz and sdw used to belong to mapthiv (was it renamed to mathiw?)

This might be useful info - in the bindings file I see:

...

mpathiv 20024f400d5190010                      <---------------------------------------- this is the scsi_sn of sdag

mpathiw 20024f400d5190026                     <---------------------------------------- this is the scsi_sn of sdz/w

...


I am adding the relevant host logs (I can add the full logs if needed) - error is in the last log line:

Mar 14 09:44:36 il-ksm3-044 kernel: sdag: detected capacity change from 0 to 322122547200

Mar 14 09:59:35 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Warning! Received an indication that the LUN reached a thin provisioning soft threshold.

Mar 14 10:00:06 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Warning! Received an indication that the LUN reached a thin provisioning soft threshold.

Mar 14 10:00:21 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Warning! Received an indication that the LUN reached a thin provisioning soft threshold.

Mar 14 10:26:31 il-ksm3-044 kernel: end_request: I/O error, dev sdz, sector 167369280
Mar 14 10:26:31 il-ksm3-044 kernel: end_request: I/O error, dev sdz, sector 80032448

Mar 14 10:26:44 il-ksm3-044 multipathd: sdz: remove path (uevent)
Mar 14 10:26:44 il-ksm3-044 multipathd: sdz [65:144]: path removed from map mpathiv
Mar 14 10:26:44 il-ksm3-044 multipathd: sdag: remove path (uevent)
Mar 14 10:26:44 il-ksm3-044 multipathd: sdag [66:0]: path removed from map mpathks

Mar 14 10:26:44 il-ksm3-044 multipathd: mpathiv: load table [0 209715200 multipath 0 0 1 1 queue-length 0 1 1 65:96 1]
Mar 14 10:26:44 il-ksm3-044 multipathd: mpathks: load table [0 629145600 multipath 0 0 1 1 queue-length 0 1 1 65:240 1]

Mar 14 10:53:50 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] 209715200 512-byte logical blocks: (107 GB/100 GiB)
Mar 14 10:53:50 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] Write Protect is off
Mar 14 10:53:50 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] Write cache: disabled, read cache: enabled, supports DPO and FUA
Mar 14 10:53:50 il-ksm3-044 kernel: sdz:
Mar 14 10:53:50 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] Attached SCSI disk
Mar 14 10:53:50 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] 629145600 512-byte logical blocks: (322 GB/300 GiB)
Mar 14 10:53:50 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Write Protect is off
Mar 14 10:53:50 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Write cache: disabled, read cache: enabled, supports DPO and FUA
Mar 14 10:53:50 il-ksm3-044 kernel: sdag: unknown partition table
Mar 14 10:53:50 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Attached SCSI disk
Mar 14 10:53:50 il-ksm3-044 multipathd: sdag: add path (uevent)
Mar 14 10:53:50 il-ksm3-044 multipathd: mpathks: failed in domap for addition of new path sdag
Mar 14 10:53:50 il-ksm3-044 multipathd: sdz: add path (uevent)
Mar 14 10:53:50 il-ksm3-044 multipathd: sdz [65:144]: path added to devmap mpathiv

Mar 14 10:53:50 il-ksm3-044 multipathd: mpathiv: load table [0 209715200 multipath 0 0 1 1 queue-length 0 2 1 65:96 1 65:144 1]

Mar 14 12:29:12 il-ksm3-044 multipathd: sdw: remove path (uevent)
Mar 14 12:29:12 il-ksm3-044 multipathd: mpathiv: load table [0 209715200 multipath 0 0 1 1 queue-length 0 1 1 65:144 1]
Mar 14 12:29:12 il-ksm3-044 multipathd: sdw [65:96]: path removed from map mpathiv

Mar 15 12:45:59 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] Warning! Received an indication that the LUN assignments on this target have changed. The Linux SCSI layer does not automatically remap LUN assignments.

Mar 14 12:59:18 il-ksm3-044 kernel: sd 7:0:1:11: [sdw] 209715200 512-byte logical blocks: (107 GB/100 GiB)
Mar 14 12:59:18 il-ksm3-044 kernel: sd 7:0:1:11: [sdw] Write Protect is off
Mar 14 12:59:18 il-ksm3-044 kernel: sd 7:0:1:11: [sdw] Write cache: disabled, read cache: enabled, supports DPO and FUA
Mar 14 12:59:18 il-ksm3-044 kernel: sd 7:0:1:11: [sdw] Attached SCSI disk

Mar 14 12:59:18 il-ksm3-044 multipathd: sdw: add path (uevent)
Mar 14 12:59:18 il-ksm3-044 multipathd: mpathiv: load table [0 209715200 multipath 0 0 1 1 queue-length 0 2 1 65:144 1 65:96 1]
Mar 14 12:59:18 il-ksm3-044 multipathd: sdw [65:96]: path added to devmap mpathiv

Mar 15 11:45:27 il-ksm3-044 kernel: sdz: detected capacity change from 0 to 107374182400

Mar 15 11:45:33 il-ksm3-044 multipathd: mpathiw: event checker started
Mar 15 11:45:33 il-ksm3-044 multipathd: mpathiw: devmap dm-13 added

Mar 15 12:28:12 il-ksm3-044 multipathd: mpathiw: event checker exit

Mar 15 12:28:15 il-ksm3-044 multipathd: mpathiw: event checker started
Mar 15 12:28:15 il-ksm3-044 multipathd: mpathiw: devmap dm-13 added

Mar 15 12:56:35 il-ksm3-044 kernel: end_request: I/O error, dev sdz, sector 204563968
Mar 15 12:56:35 il-ksm3-044 kernel: end_request: I/O error, dev sdz, sector 193484032
Mar 15 12:56:35 il-ksm3-044 multipathd: mpathiw: remaining active paths: 1

Mar 15 12:56:48 il-ksm3-044 multipathd: sdz: remove path (uevent)
Mar 15 12:56:48 il-ksm3-044 multipathd: mpathiw: load table [0 209715200 multipath 0 0 1 1 queue-length 0 1 1 65:96 1]
Mar 15 12:56:48 il-ksm3-044 multipathd: sdz [65:144]: path removed from map mpathiw
Mar 15 12:56:48 il-ksm3-044 multipathd: sdag: remove path (uevent)

Mar 15 13:27:00 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] 209715200 512-byte logical blocks: (107 GB/100 GiB)
Mar 15 13:27:00 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] Write Protect is off
Mar 15 13:27:00 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] Write cache: disabled, read cache: enabled, supports DPO and FUA
Mar 15 13:27:00 il-ksm3-044 kernel: sdz: unknown partition table
Mar 15 13:27:00 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] Attached SCSI disk
Mar 15 13:27:00 il-ksm3-044 multipathd: sdz: add path (uevent)
Mar 15 13:27:00 il-ksm3-044 multipathd: mpathiw: failed in domap for addition of new path sdz

Mar 15 15:20:41 il-ksm3-044 multipathd: mpathiw: devmap dm-13 added

Mar 15 17:38:36 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] Warning! Received an indication that the LUN assignments on this target have changed. The Linux SCSI layer does not automatically remap LUN assignments.

Mar 15 18:44:54 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] 629145600 512-byte logical blocks: (322 GB/300 GiB)
Mar 15 18:44:54 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Write Protect is off
Mar 15 18:44:54 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Write cache: disabled, read cache: enabled, supports DPO and FUA
Mar 15 18:44:54 il-ksm3-044 kernel: sdag: unknown partition table
Mar 15 18:44:54 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Attached SCSI disk

Mar 15 18:44:55 il-ksm3-044 multipathd: sdag: add path (uevent)
Mar 15 18:44:55 il-ksm3-044 multipathd: mpathiw: load table [0 209715200 multipath 0 0 1 1 queue-length 0 3 1 65:96 1 65:144 1 66:0 1]
Mar 15 18:44:55 il-ksm3-044 multipathd: sdag [66:0]: path added to devmap mpathiw

Thank you,
Ilan Steinberg

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^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: A path to a different device was added to an existing mapth
  2015-03-19 10:10 A path to a different device was added to an existing mapth Ilan Steinberg
@ 2015-03-19 10:35 ` Ilan Steinberg
  2015-03-27 23:26   ` Stewart, Sean
  0 siblings, 1 reply; 4+ messages in thread
From: Ilan Steinberg @ 2015-03-19 10:35 UTC (permalink / raw)
  To: dm-devel@redhat.com; +Cc: Guy Keren, Eli Malul, Shahar Salzman


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Hi,


I have some more info:


multipathd> show maps
name    sysfs uuid
mpathhs dm-2  20024f400d5190000
mpathit dm-16 20024f400d519002b
mpathis dm-15 20024f400d519001c
mpathin dm-11 20024f400d5190012
mpathim dm-14 20024f400d5190011
mpathiw dm-13 20024f400d5190010
mpathhz dm-7  20024f400d5190006
mpathhx dm-6  20024f400d5190005
mpathhw dm-5  20024f400d5190004
mpathht dm-8  20024f400d5190003
mpathij dm-12 20024f400d519000e
mpathil dm-10 20024f400d519000d
mpathhv dm-3  20024f400d5190001
mpathik dm-9  20024f400d519000f
mpathhu dm-4  20024f400d5190002


It seems that mpathiw is indeed with the uuid of sdag but...


note that  if you run 'multipath -l' you will see mpathiw having the correct
signature (20024f400d5190026) - because it queries it again from the storage.


Also:


multipathd> show paths format "%d %s %S %w"
dev  vend/prod/rev size uuid
.
.
sdaf KMNRIO,K2     300G 20024f400d519001e
.
sdw  KMNRIO,K2     100G 20024f400d5190010
.
.
sdz  KMNRIO,K2     100G 20024f400d5190026
.
sdag KMNRIO,K2     300G 20024f400d5190010


Unfortunately, the device for sdag was deleted from the storage, but I can still see that:

[root@il-ksm3-044 ~]# sg_inq -p 0x83 /dev/sdw
VPD INQUIRY: Device Identification page
  Designation descriptor number 1, descriptor length: 36
    designator_type: T10 vendor identification,  code_set: ASCII
    associated with the addressed logical unit
      vendor id: KMNRIO
      vendor specific: ATF-VG-1:EXP-SNAd5190026
  Designation descriptor number 2, descriptor length: 12
    designator_type: EUI-64 based,  code_set: Binary
    associated with the addressed logical unit
      EUI-64 based 8 byte identifier
      IEEE Company_id: 0x24f4
      Vendor Specific Extension Identifier: 0xd5190026
      [0x0024f400d5190026]
[root@il-ksm3-044 ~]# sg_inq -p 0x83 /dev/sdz
VPD INQUIRY: Device Identification page
  Designation descriptor number 1, descriptor length: 36
    designator_type: T10 vendor identification,  code_set: ASCII
    associated with the addressed logical unit
      vendor id: KMNRIO
      vendor specific: ATF-VG-1:EXP-SNAd5190026
  Designation descriptor number 2, descriptor length: 12
    designator_type: EUI-64 based,  code_set: Binary
    associated with the addressed logical unit
      EUI-64 based 8 byte identifier
      IEEE Company_id: 0x24f4
      Vendor Specific Extension Identifier: 0xd5190026
      [0x0024f400d5190026]

So, sdw and sdz are path to the same device, and so are sdaf and sdag...

Regards,
Ilan Steinberg


________________________________
From: Ilan Steinberg
Sent: Thursday, March 19, 2015 12:10 PM
To: dm-devel@redhat.com
Cc: Eli Malul; Guy Keren; Shahar Salzman
Subject: A path to a different device was added to an existing mapth


Hello,


I have never posted here before but I can across an interesting error.


I have run into a situation were a path (sdag) to LUN 15 with a scsi serial number of ending with 0xd5190010 was added to an mapth (mpathiw) which is for LUN 11 with scsi serial number ending with 0xd5190026 (sdz and sdw)


I would appreciate any help understanding how/why this happened.


Initiator Info:

Linux il-ksm3-044 2.6.32-431.el6.x86_64 #1

device-mapper-multipath version 0.4.9


multipath.conf:

defaults {
                   user_friendly_names     yes
                   polling_interval        10
                    verbosity               2
}
devices {
                    device  {
                             vendor                      "KMNRIO"
                             product                     "K2"
                         path_grouping_policy        multibus
                             getuid_callout          "/lib/udev/scsi_id --whitelisted --device=/dev/%n"
                             path_checker                tur
                             path_selector               "queue-length 0"
                             no_path_retry               fail
                             hardware_handler            "0"
                             rr_weight                   priorities
                             rr_min_io               1
                             failback                15
                             fast_io_fail_tmo        5
                             dev_loss_tmo            8
                             }
}


Since I see that sdz and sdw used to belong to mapthiv (was it renamed to mathiw?)

This might be useful info - in the bindings file I see:

...

mpathiv 20024f400d5190010                      <---------------------------------------- this is the scsi_sn of sdag

mpathiw 20024f400d5190026                     <---------------------------------------- this is the scsi_sn of sdz/w

...


I am adding the relevant host logs (I can add the full logs if needed) - error is in the last log line:

Mar 14 09:44:36 il-ksm3-044 kernel: sdag: detected capacity change from 0 to 322122547200

Mar 14 09:59:35 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Warning! Received an indication that the LUN reached a thin provisioning soft threshold.

Mar 14 10:00:06 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Warning! Received an indication that the LUN reached a thin provisioning soft threshold.

Mar 14 10:00:21 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Warning! Received an indication that the LUN reached a thin provisioning soft threshold.

Mar 14 10:26:31 il-ksm3-044 kernel: end_request: I/O error, dev sdz, sector 167369280
Mar 14 10:26:31 il-ksm3-044 kernel: end_request: I/O error, dev sdz, sector 80032448

Mar 14 10:26:44 il-ksm3-044 multipathd: sdz: remove path (uevent)
Mar 14 10:26:44 il-ksm3-044 multipathd: sdz [65:144]: path removed from map mpathiv
Mar 14 10:26:44 il-ksm3-044 multipathd: sdag: remove path (uevent)
Mar 14 10:26:44 il-ksm3-044 multipathd: sdag [66:0]: path removed from map mpathks

Mar 14 10:26:44 il-ksm3-044 multipathd: mpathiv: load table [0 209715200 multipath 0 0 1 1 queue-length 0 1 1 65:96 1]
Mar 14 10:26:44 il-ksm3-044 multipathd: mpathks: load table [0 629145600 multipath 0 0 1 1 queue-length 0 1 1 65:240 1]

Mar 14 10:53:50 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] 209715200 512-byte logical blocks: (107 GB/100 GiB)
Mar 14 10:53:50 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] Write Protect is off
Mar 14 10:53:50 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] Write cache: disabled, read cache: enabled, supports DPO and FUA
Mar 14 10:53:50 il-ksm3-044 kernel: sdz:
Mar 14 10:53:50 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] Attached SCSI disk
Mar 14 10:53:50 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] 629145600 512-byte logical blocks: (322 GB/300 GiB)
Mar 14 10:53:50 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Write Protect is off
Mar 14 10:53:50 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Write cache: disabled, read cache: enabled, supports DPO and FUA
Mar 14 10:53:50 il-ksm3-044 kernel: sdag: unknown partition table
Mar 14 10:53:50 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Attached SCSI disk
Mar 14 10:53:50 il-ksm3-044 multipathd: sdag: add path (uevent)
Mar 14 10:53:50 il-ksm3-044 multipathd: mpathks: failed in domap for addition of new path sdag
Mar 14 10:53:50 il-ksm3-044 multipathd: sdz: add path (uevent)
Mar 14 10:53:50 il-ksm3-044 multipathd: sdz [65:144]: path added to devmap mpathiv

Mar 14 10:53:50 il-ksm3-044 multipathd: mpathiv: load table [0 209715200 multipath 0 0 1 1 queue-length 0 2 1 65:96 1 65:144 1]

Mar 14 12:29:12 il-ksm3-044 multipathd: sdw: remove path (uevent)
Mar 14 12:29:12 il-ksm3-044 multipathd: mpathiv: load table [0 209715200 multipath 0 0 1 1 queue-length 0 1 1 65:144 1]
Mar 14 12:29:12 il-ksm3-044 multipathd: sdw [65:96]: path removed from map mpathiv

Mar 15 12:45:59 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] Warning! Received an indication that the LUN assignments on this target have changed. The Linux SCSI layer does not automatically remap LUN assignments.

Mar 14 12:59:18 il-ksm3-044 kernel: sd 7:0:1:11: [sdw] 209715200 512-byte logical blocks: (107 GB/100 GiB)
Mar 14 12:59:18 il-ksm3-044 kernel: sd 7:0:1:11: [sdw] Write Protect is off
Mar 14 12:59:18 il-ksm3-044 kernel: sd 7:0:1:11: [sdw] Write cache: disabled, read cache: enabled, supports DPO and FUA
Mar 14 12:59:18 il-ksm3-044 kernel: sd 7:0:1:11: [sdw] Attached SCSI disk

Mar 14 12:59:18 il-ksm3-044 multipathd: sdw: add path (uevent)
Mar 14 12:59:18 il-ksm3-044 multipathd: mpathiv: load table [0 209715200 multipath 0 0 1 1 queue-length 0 2 1 65:144 1 65:96 1]
Mar 14 12:59:18 il-ksm3-044 multipathd: sdw [65:96]: path added to devmap mpathiv

Mar 15 11:45:27 il-ksm3-044 kernel: sdz: detected capacity change from 0 to 107374182400

Mar 15 11:45:33 il-ksm3-044 multipathd: mpathiw: event checker started
Mar 15 11:45:33 il-ksm3-044 multipathd: mpathiw: devmap dm-13 added

Mar 15 12:28:12 il-ksm3-044 multipathd: mpathiw: event checker exit

Mar 15 12:28:15 il-ksm3-044 multipathd: mpathiw: event checker started
Mar 15 12:28:15 il-ksm3-044 multipathd: mpathiw: devmap dm-13 added

Mar 15 12:56:35 il-ksm3-044 kernel: end_request: I/O error, dev sdz, sector 204563968
Mar 15 12:56:35 il-ksm3-044 kernel: end_request: I/O error, dev sdz, sector 193484032
Mar 15 12:56:35 il-ksm3-044 multipathd: mpathiw: remaining active paths: 1

Mar 15 12:56:48 il-ksm3-044 multipathd: sdz: remove path (uevent)
Mar 15 12:56:48 il-ksm3-044 multipathd: mpathiw: load table [0 209715200 multipath 0 0 1 1 queue-length 0 1 1 65:96 1]
Mar 15 12:56:48 il-ksm3-044 multipathd: sdz [65:144]: path removed from map mpathiw
Mar 15 12:56:48 il-ksm3-044 multipathd: sdag: remove path (uevent)

Mar 15 13:27:00 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] 209715200 512-byte logical blocks: (107 GB/100 GiB)
Mar 15 13:27:00 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] Write Protect is off
Mar 15 13:27:00 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] Write cache: disabled, read cache: enabled, supports DPO and FUA
Mar 15 13:27:00 il-ksm3-044 kernel: sdz: unknown partition table
Mar 15 13:27:00 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] Attached SCSI disk
Mar 15 13:27:00 il-ksm3-044 multipathd: sdz: add path (uevent)
Mar 15 13:27:00 il-ksm3-044 multipathd: mpathiw: failed in domap for addition of new path sdz

Mar 15 15:20:41 il-ksm3-044 multipathd: mpathiw: devmap dm-13 added

Mar 15 17:38:36 il-ksm3-044 kernel: sd 8:0:1:11: [sdz] Warning! Received an indication that the LUN assignments on this target have changed. The Linux SCSI layer does not automatically remap LUN assignments.

Mar 15 18:44:54 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] 629145600 512-byte logical blocks: (322 GB/300 GiB)
Mar 15 18:44:54 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Write Protect is off
Mar 15 18:44:54 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Write cache: disabled, read cache: enabled, supports DPO and FUA
Mar 15 18:44:54 il-ksm3-044 kernel: sdag: unknown partition table
Mar 15 18:44:54 il-ksm3-044 kernel: sd 8:0:1:15: [sdag] Attached SCSI disk

Mar 15 18:44:55 il-ksm3-044 multipathd: sdag: add path (uevent)
Mar 15 18:44:55 il-ksm3-044 multipathd: mpathiw: load table [0 209715200 multipath 0 0 1 1 queue-length 0 3 1 65:96 1 65:144 1 66:0 1]
Mar 15 18:44:55 il-ksm3-044 multipathd: sdag [66:0]: path added to devmap mpathiw

Thank you,
Ilan Steinberg

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^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: A path to a different device was added to an existing mapth
  2015-03-19 10:35 ` Ilan Steinberg
@ 2015-03-27 23:26   ` Stewart, Sean
  2015-03-28 11:32     ` guy keren
  0 siblings, 1 reply; 4+ messages in thread
From: Stewart, Sean @ 2015-03-27 23:26 UTC (permalink / raw)
  To: device-mapper development; +Cc: Guy Keren, Eli Malul, Shahar Salzman

Hi Ilan,

I believe this is solved by the following patch:
http://git.opensvc.com/gitweb.cgi?p=multipath-tools/.git;a=commit;h=5adec73edcdee912821ca8378439dc105e82c60f 

Per the patch description:
When a system is booted to the SAN, a condition can occur where one
user friendly name is given to a disk during boot, but multipathd tries
to allocate a different one after boot. If the second alias is already
used by another device, multipathd can't rename it. Multipathd then has
incorrect information about the alias/wwid relationships, which can
result in paths being added to the wrong map.

On Thu, 2015-03-19 at 10:35 +0000, Ilan Steinberg wrote:

> multipathd> show maps
> name    sysfs uuid
> mpathiw dm-13 20024f400d5190010

This shows the current running configuration, that multipathd is
operating believing that mpathiw should have be 20024f400d5190010. 

> This might be useful info - in the bindings file I see:
> 
> ...
> 
> mpathiv 20024f400d5190010
> <---------------------------------------- this is the scsi_sn of sdag
> 
> mpathiw 20024f400d5190026
> <---------------------------------------- this is the scsi_sn of sdz/w
> 
> ...
> 
So what must have happened was that the bindings file was out of sync on
the initramfs and the local fs (which you can check by unwrapping the
initramfs and comparing the wwids in each file), and it created the
device with one name, tried to rename it, couldn't, and multipathd then
starts adding into the wrong map. It's hard to explain clearly. :)  If
we could see what both bindings files say, maybe I could explain it
better.

To work around it, remaking the initramfs to sync the bindings should
suffice, or you could define aliases via the multipath sections
multipath.conf.

Hope this helps.

Thanks,
Sean Stewart

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: A path to a different device was added to an existing mapth
  2015-03-27 23:26   ` Stewart, Sean
@ 2015-03-28 11:32     ` guy keren
  0 siblings, 0 replies; 4+ messages in thread
From: guy keren @ 2015-03-28 11:32 UTC (permalink / raw)
  To: Stewart, Sean, device-mapper development; +Cc: Eli Malul, Shahar Salzman


hi Sean,

in the case stated, the host was not rebooted during this test. what has 
changed is LUNs exposure to the host (unmapping and re-mapping of LUNs, 
deleting and re-creating of LUNs).

could these kind of operations trigger similar issues?

from what we saw, multipathd's state made it think that some paths, that 
have different WWIDs, should be bound to the same multipath device 
(which is incorrect).

a different question comes to mind:

   if we avoid using the friendly names, and instead use the 
/dev/mapper/<wwid> device paths - is this likely to avoid the problem in 
the first place?

--guy


On 03/28/2015 02:26 AM, Stewart, Sean wrote:
> Hi Ilan,
>
>
> I believe this is solved by the following patch:
> http://git.opensvc.com/gitweb.cgi?p=multipath-tools/.git;a=commit;h=5adec73edcdee912821ca8378439dc105e82c60f
>
> Per the patch description:
> When a system is booted to the SAN, a condition can occur where one
> user friendly name is given to a disk during boot, but multipathd tries
> to allocate a different one after boot. If the second alias is already
> used by another device, multipathd can't rename it. Multipathd then has
> incorrect information about the alias/wwid relationships, which can
> result in paths being added to the wrong map.
>
> On Thu, 2015-03-19 at 10:35 +0000, Ilan Steinberg wrote:
>
>> multipathd> show maps
>> name    sysfs uuid
>> mpathiw dm-13 20024f400d5190010
> This shows the current running configuration, that multipathd is
> operating believing that mpathiw should have be 20024f400d5190010.
>
>> This might be useful info - in the bindings file I see:
>>
>> ...
>>
>> mpathiv 20024f400d5190010
>> <---------------------------------------- this is the scsi_sn of sdag
>>
>> mpathiw 20024f400d5190026
>> <---------------------------------------- this is the scsi_sn of sdz/w
>>
>> ...
>>
> So what must have happened was that the bindings file was out of sync on
> the initramfs and the local fs (which you can check by unwrapping the
> initramfs and comparing the wwids in each file), and it created the
> device with one name, tried to rename it, couldn't, and multipathd then
> starts adding into the wrong map. It's hard to explain clearly. :)  If
> we could see what both bindings files say, maybe I could explain it
> better.
>
> To work around it, remaking the initramfs to sync the bindings should
> suffice, or you could define aliases via the multipath sections
> multipath.conf.
>
> Hope this helps.
>
>
> Thanks,
> Sean Stewart
>
>

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2015-03-28 11:32 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2015-03-19 10:10 A path to a different device was added to an existing mapth Ilan Steinberg
2015-03-19 10:35 ` Ilan Steinberg
2015-03-27 23:26   ` Stewart, Sean
2015-03-28 11:32     ` guy keren

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