volume groups are inaccessible after deallocating & allocating lun in san

[QASCO]

Hello experts,
we were doing san size rearrangement, giving back san disk to san pool & allocating a larger lun.
we come accross strange issue that luns are assigned different device files than they were before, this issue comes up after system restart.
now due to this some volume groups became in accessible since the device files either changed or simply not there like device files not there in ioscan but available in lvmtab.

Any idea why this is happening or if there is procedure to decomission a lun & allocate later.

Any help is higly appreciated.
Regards,

[Pete Randall]

Try vgscan.

mv /etc/lvmtab /etc/lvmtab.save
vgscan -a


Pete

[QASCO]

Thanks pete,but i have already lost one file system & recovered from the backup.

could somebody hightlight the steps required to deallocate a lun & allocate diffrent lun from the operationg system & from the san.

regards,

[Jean-Yves Picard]

Hello,

I don't know if it is still true, but lun ought to be consecutive number (e.g. 0, 1, 2, 3) with no hole.

(feel free to give more information, like OS version, which SAN, ...)

Jean-Yves

[saju_2]

Hi

Do u have a map file of the VG's with -s option?

U can import a VG eventhough the device files got changed. vgimport -s option searches for the unique VGID in the entire storage and imports the disks which are found with that particular unique VGID.

Regards
CS

[QASCO]

Well, i dont have a map file.

My HPUX box model is 5470 with hpux 11i & san is EVA 5000.

I used to do the following to deallocate & allocate alun.

1> vgchange -a n vgxx
2> vgexport vg xx
3> then lun is removed from san & then another lun is presented to O.S.
4> ioscan -funC disk.
5 > pvcreate(sam).
6> vgcreate(sam).
7> lvcreate(sam).

Any mistake in the above procedure.

Regards,

[Sยภเl Kย๓คг]

Hi,

I feel the mistake which u have done is ,
in step 4> ioscan -funC disk, this won't do a physical disk scan, this will just disply the the hardwares, class disk which is reported in the kernel(Means old disks only).
Your 4th step should have been

4>#ioscan -fnC disk
5>#insf

step 4 will do a physical hardware scan for disks. step 5 will load apporpriate disk drivers. Any how what u need to do is now to created every thing from scratch.

Since your server is already rebooted, u don't need to now perform step 4 and step 5 which I have mentioned. This would have already done when the system booted up. That's the reason you are getting different path names and ur filesystems are not mounted.

proceed with
5 > pvcreate
6> vgcreate
7> lvcreate

Regards,
Sunil

[QASCO]

Hi Sunil,

insf is done even though i did not mention it.
Regards,