[linux-lvm] multipath works; lvm on multipath does not
finley at anl.gov
finley at anl.gov
Wed Jul 15 21:53:17 UTC 2009
How can I tell what is causing LVM on multipath volumes to fail, while direct multipath volumes are working?
The details:
I have several volumes that are multipathed over fibre channel (2 qlogic cards in the host) from a Fujitsu Eternus 4000 (4 controllers).
When using a file system mounted on the dm-multipath device directly (Ie.: generating I/O via IOZone), it fails over gracefully when I pull out either of the fibre pairs, and the file system continues to operate. This device is called /dev/mapper/zimbra-mb1-t2-v4_fujitsu1-lun66.
However, when I access an LVM volume created with sister devices as PVs, the LVM presented volume does not fail over. Rather the LV device goes inaccessible and the file system (ext3) re-mounts itself as read-only. If I try to access any of the underlying PVs, they still respond as available (Ie.: fdisk -l $PV).
I am not seeing duplicate devices, and am using the following filter in /etc/lvm/lvm.conf:
filter = [ "a|^/dev/md.*|", "a|^/dev/mapper/zimbra-mb.*-t.*-v.*_.*-lun.*|", "r|.*|" ]
I have also added the following, but dm-multipath devices seem usable by LVM with or without this setting:
types = [ "device-mapper", 1 ]
I have tried removing the /etc/lvm/cache/.cache file, but that seems to have had no effect. I've also tried re-building the initrd after modifying the lvm.conf file, also with no effect.
Additional info:
root at zimbra-mb1:~# pvs
PV VG Fmt Attr PSize PFree
/dev/mapper/zimbra-mb1-t1-v1_fujitsu1-lun55 mb1_t1 lvm2 a- 195.31G 60.31G
/dev/mapper/zimbra-mb1-t1-v2_fujitsu1-lun56 mb1_t1 lvm2 a- 195.31G 60.31G
/dev/mapper/zimbra-mb1-t1-v3_fujitsu1-lun57 mb1_t1 lvm2 a- 195.31G 60.31G
/dev/mapper/zimbra-mb1-t1-v4_fujitsu1-lun58 mb1_t1 lvm2 a- 195.31G 60.31G
/dev/mapper/zimbra-mb1-t2-v1_fujitsu1-lun63 mb1_t2 lvm2 a- 504.00G 4.00G
/dev/mapper/zimbra-mb1-t2-v2_fujitsu1-lun64 mb1_t2 lvm2 a- 488.28G 0
/dev/mapper/zimbra-mb1-t2-v3_fujitsu1-lun65 mb1_t2 lvm2 a- 195.31G 195.31G
/dev/mapper/zimbra-mb1-t2-v5_fujitsu1-lun67 mb1_t2 lvm2 a- 354.37G 0
/dev/mapper/zimbra-mb1-t2-v6_fujitsu1-lun68 mb1_t2 lvm2 a- 234.56G 77.21G
/dev/md1 zimbra-mb1 lvm2 a- 136.50G 83.50G
kernel version: 2.6.24-24-server
distoro: Ubuntu Hardy
multipath-tools: 0.4.8-7ubuntu2
lvm2: 2.02.26-1ubuntu9
Thanks!
-Brian
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