topic Re: Possible Ghost Disk? in Operating System - HP-UX

Possible Ghost Disk?

Jamin Miser_3 — Sun, 04 Sep 2005 10:22:24 GMT

Hello.

I cannot mount my Logical Volume 7:

# mount /xxx
vxfs mount: /dev/vg00/lvol7 is corrupted. needs checking

On Friday Disks c2t6d0 & c5t10d0 did not show up in IOSCAN.
We replaced these disks on Saturday.

I am trying to determine where my problem lies. I believe I have a bad disk, but a dd comes back fine.

I am running MirrorDisk UX, so if one of the disks is bad, I SHOULD still be able to get to the primary, but no dice.

An lvdisplay turns up REALLY weird information:

01998 /dev/dsk/c1t3d0 01323 current /dev/dsk/c5t10d0 01225 current
01999 /dev/dsk/c1t3d0 01324 current /dev/dsk/c5t10d0 01226 current
02000 /dev/dsk/c5t10d0 01777 stale ??? 00000 current
02001 /dev/dsk/c5t10d0 01778 stale ??? 00001 current
02002 /dev/dsk/c5t10d0 01779 stale ??? 00002 current

02391 /dev/dsk/c5t10d0 02168 stale ??? 00391 current
02392 /dev/dsk/c5t10d0 02169 stale ??? 00392 current
02393 ??? 00393 stale /dev/dsk/c1t2d0 00000 current
02394 ??? 00394 stale /dev/dsk/c1t2d0 00001 current
02395 ??? 00395 stale /dev/dsk/c1t2d0 00002 current
02396 ??? 00396 stale /dev/dsk/c1t2d0 00003 current

I believe the Problem is the Ghost Disk issue that I have seen if forums.
vgdisplay shows that I have 9 current disks, but only 8 active disks.
I SHOULD only have 8 disks.

Using the "-k" option with lvdisplay, I was able to determine that the disk key of the "Ghost Disk" is 6.
I tried to do an lvreduce, also with the "-k option. This did not work. It would not let me remove the
Ghost Disk from the logical volume because there were stale Extents

At first, disk: c5t10d0 didn't show up in ioscan, but now it does.

Also, A disk that I am not using is popping up with errors:
# vgcfgrestore -n /dev/vg00 /dev/rdsk/c5t10d0
vgcfgrestore: Couldn't query physical volume "/dev/dsk/c2t6d0":
The specified path does not correspond to physical volume attached to
this volume group

More info:
# strings /etc/lvmtab
/dev/vg00
/dev/dsk/c1t2d0
/dev/dsk/c1t3d0
/dev/dsk/c1t4d0
/dev/dsk/c1t5d0
/dev/dsk/c5t8d0
/dev/dsk/c5t9d0
/dev/dsk/c5t10d0
/dev/dsk/c5t11d0

I am on HP/UX 11.0
patch bundle is for year 2001 !!!

ANY help is appreciated.

Let me know if more information is needed.

Thanks!

Re: Possible Ghost Disk?

Robert-Jan Goossens — Sun, 04 Sep 2005 12:21:53 GMT

could you post the complete output of "vgdisplay -v vg00" and "lvdisplay -v /dev/vg00/lvol7" ?

Regards,
Robert-Jan

Re: Possible Ghost Disk?

Steven E. Protter — Sun, 04 Sep 2005 13:29:24 GMT

Pending the fulfillment of Robert's information request, I'd consider trying to break the mirror and then lvreduce.

SEP

Re: Possible Ghost Disk?

Jamin Miser_3 — Sun, 04 Sep 2005 13:50:53 GMT

The only thing I was able to do was to remove the Logical Volume, then re-create it.

That seemed to clear up the Ghost Disk problem.

I am now restoring from backup.

Thanks to everyone that replied!

Re: Possible Ghost Disk?

Sameer_Nirmal — Sun, 04 Sep 2005 17:22:45 GMT

Let me put the points based on whatever you have mentioned here.

It seems that the disk c2t6d0 failed to respond withing the limit it is supposed to.
Thats why you see stale logical extends, as this disk had mirrored PEs/LEs of some lvols on both c5t10d0 & c1t2d0.

Then disk c2t6d0 was removed from the system physically ( being diagnosed as bad ) but it remained in the lvmtab and became the "Ghost Disk"!!!! . But this ghost
should be there in lvmtab as well besides showing in vgdisplay. I am surprised to see that lvmtab . Did you recreate the lvmtab using vgscan after removing c2t6d0 ?? and I bet you did.

Now later when you tried to run vgcfgrestore on c5t10d0 , it's quite obvious it will give that error.
Had the lvmtab intact and c2t6d0 replaced with a new disk , vgrestore could have worked
assuming good c5t10d0.

Incidently the same disk c2t6d0 apprears to be the primary/master mirror copy of the lvol7. It could have been possible to access the data of lvol7 since it was mirrored just by removing the disk c2t6d0 by remvoing its PEs/LEs references first using lvreduce -k and then running vgreduce -f .