[Bug 985741] Re: multipath can't show device on which is setup lvm

[David Duffey]

Hi Vencent, 

Here are some things you can try that might help narrow the problem:

* Re-create the init ramdisk, make sure your storage module is in the initrd
   (what modules are in the initrd, vs what modules are loaded after boot and everything
    is working)
* Can you test this on 12.04 LTS (released April 26th) to see if it has the same behaviour?
* Show the output of multipathd -k"show config"
* Give the output of the following commands before creating the lv, after, and after reboot
   * dmsetup ls --tree
   * dmsetup table

I suspect this can be fixed in the initrd.

David

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https://bugs.launchpad.net/bugs/985741

Title:
  multipath can't show device on which is setup lvm

Status in “multipath-tools” package in Ubuntu:
  Confirmed

Bug description:
  root at SGELLIN119:~# lsb_release -rd
  Description:    Ubuntu 11.10
  Release:        11.10

  affect package: multipath-tools, lvm2

  If  creating logical volume with Multipath on disk primary partition 1, multipath can’t find the 
  disks. Syslog show  such error when booting system

  kernel: [   27.604034] device-mapper: table: 252:5: multipath: error getting device
  kernel: [   27.604115] device-mapper: ioctl: error adding target to table

  
  I use fdisk to create two partitions on one physical lun.

  Mpath6:
  /dev/mapper/mpath6-part1
  /dev/mapper/mpath6-part2

  Mpath7:
  /dev/mapper/mpath7-part1
  /dev/mapper/mpath7-part2

  create a logical volume on  mpath6-part2, mpath7-part2
  Reboot  host, there is no exception and error logs. Multipath could
  Find all devices.

  root at SGELLIN119:~# multipath -ll | grep SYMM
  mpath9 (360000970000192602316533030453335) dm-10 EMC,SYMMETRIX
  mpath8 (360000970000192602316533030453334) dm-6 EMC,SYMMETRIX
  mpath7 (360000970000192602316533030453333) dm-7 EMC,SYMMETRIX
  mpath6 (360000970000192602316533030453332) dm-4 EMC,SYMMETRIX
  mpath5 (360000970000192602316533030453331) dm-3 EMC,SYMMETRIX

  
  root at SGELLIN119:~# lvs -v
      Finding all logical volumes
    LV      VG      #Seg Attr   LSize    Maj Min KMaj KMin Origin Snap%  Move Copy%  Log Convert LV UUID                       
    mlv     my_vg      1 -wi-a- 1020.00m  -1  -1 252  22                                         c3cECW-CJry-OdXI-O9bZ-lXq8-BUYq-obzcvB
    sym_lv2 sym_vg2    2 -wi-a-  200.00m  -1  -1 252  20                                         1t9SZa-QEEm-2u6p-lCqN-aqcd-xOpn-dC1YAu
    sym_lv3 sym_vg3    2 -wi-a-  200.00m  -1  -1 252  21                                         w4H00r-l71s-UURm-C32C-wDuS-fEF2-wlJFI0

  Then I use same way to create a lv on mpath6-part1 and mpath7-part1
  After rebooting host,  there are some error logs happen. 
  Multipath can’t find mpath6 and mapth7.  Of course the logical volums on
  Mpath6 and mpath7 were lost also.

  
  root at SGELLIN119:~# multipath -ll| grep SYMM
  mpath9 (360000970000192602316533030453335) dm-3 EMC,SYMMETRIX
  mpath8 (360000970000192602316533030453334) dm-2 EMC,SYMMETRIX
  mpath5 (360000970000192602316533030453331) dm-5 EMC,SYMMETRIX

  
  root at SGELLIN119:~# lvs -v
      Finding all logical volumes
    LV   VG    #Seg Attr   LSize    Maj Min KMaj KMin Origin Snap%  Move Copy%  Log Convert LV UUID                            
    mlv  my_vg    1 -wi-a- 1020.00m  -1  -1 252  1                                          c3cECW-CJry-OdXI-O9bZ-lXq8-BUYq-obzcvB

  
  the finding is that if creating lvm on disk primary partition 1.  Something were changed  and it lead multipath
  couldn’t find devices.

  root at SGELLIN119:~# udevadm info --query=all --name=/dev/mapper/mpath6
  P: /devices/virtual/block/dm-8
  N: dm-8
  L: -100
  S: mapper/mpath6
  S: disk/by-id/dm-name-mpath6
  S: disk/by-id/dm-uuid-mpath-360000970000192602316533030453332
  E: UDEV_LOG=3
  E: DEVPATH=/devices/virtual/block/dm-8
  E: MAJOR=252
  E: MINOR=8
  E: DEVNAME=/dev/dm-8
  E: DEVTYPE=disk
  E: SUBSYSTEM=block
  E: DM_NAME=mpath6
  E: DM_UUID=mpath-360000970000192602316533030453332
  E: DM_SUSPENDED=0
  E: DM_UDEV_RULES=1
  E: DEVLINKS=/dev/mapper/mpath6 /dev/disk/by-id/dm-name-mpath6 /dev/disk/by-id/dm-uuid-mpath-360000970000192602316533030453332

  Value "L" is negative compare to normal one

  Here is an temporary recovery way:
  4)	Service multipath-tools stop
  5)	Dmsetup remove_all
  6)	Service multipath-tools start
  However, the issue is consistent  after I reboot OS.

  If I remove lv  ( still have LVM package in OS) ,  multipath work
  well.

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