vgchange fails after hw problems

[FERRARI MARCO]

Hi everybody.
After a problem on a SAN attached device, I cannot "vgchange -a y" my VG, created on a SAN LUN. I can see the LUN size correctly with a diskinfo.

My question is: is still good to perform a:
$ xd -j8200 -N16 -tu /dev/rdsk/c51t0d0

whiche returns as follows:

# xd -j8200 -N16 -tu /dev/rdsk/c51t0d0
0000000 0 0 0 0
0000010


And in that case, is everything zero-ed out on the LUN ?

Should I export/import the VG instead ?

Thanks,

Marco

[Fabio Ettore]

Ciao Marco,

which errors do you obtain on vgchange command?
Does 'ioscan -fnC disk' recognize the disk (I suppose yes, please confirm)?
How many disks/LUN does the VG contain?
strings /etc/lvmtab

Best regards,
Fabio

[HGN]

Hi

If you can see the diskinfo then the disks are good.What does pvdisplay show on that disk.

Rgds

HGN

[FERRARI MARCO]

Ciao.

I suspect I am trying to read zeroes, as the ioscan return is a CLAIMED.

disk 3 0/10/0/0.38.5.0.0.0.0 sdisk CLAIMED DEVICE STK XxxxxYyy ZzZz
/dev/dsk/c3t0d0 /dev/rdsk/c3t0d0

I was just asking confirmation of a good method ( if any still exists ) to extract the VGDA (supposedly zeroed out) at a fixed address of the rdsk device.

Should I run a vgscan -pv too ? Can it help when a tsunami wiped out your bytes on the remote disk ?

When I 'll be totally convinced everything is lost, I could also run a pvcreate and it should succeed instead of requiring -f.

I had a 1-LUN, 1-rdsk Volume Group.

Hope it sheds more light.

Marco

[Fabio Ettore]

Marco,

how does vgchange fail?
Th error can help to know if some actions can recover the VG.
Does the problem happen just for this VG in SAN?
What does pvdisplay show?

I don't know if there is a method to extract the VGDA, it should be good to know if someone did it before.

Best regards,
Fabio

[FERRARI MARCO]

Yes, I had got only that VG besides VG00.

Hope you aren't in my country - I've got a special activity just after midnight and so I am in the office (suppose they ask me to pay some ICI tax one day ).

Here you are with vgchange ( renamed VG ) output :

# vgchange -a y /dev/ILMIOVG
vgchange: Warning: Couldn't attach to the volume group physical volume "/dev/dsk/c3t0d0":
Cross-device link
vgchange: Warning: couldn't query physical volume "/dev/dsk/c3t0d0":
The specified path does not correspond to physical volume attached to
this volume group
vgchange: Warning: couldn't query all of the physical volumes.
vgchange: Couldn't activate volume group "/dev/ILMIOVG":
Quorum not present, or some physical volume(s) are missing.

Thanks,
Marco

[Fabio Ettore · Accepted solution]

I am in your country, Italy :-)
but not in office.

If you sure that device file for c3t0d0 is the same like before HW changes?

Check
strings /etc/lvmtab
vgcfgrestore -n /dev/ILMIOVG -l

Try

mv /etc/lvmtab /etc/lvmtab.old
vgscan -v
vgchange -a y /dev/ILMIOVG

See you tomorrow and have a nice evening!

Best regards,
Fabio

[FERRARI MARCO]

It seems now almost sure to have lost our data.
Yet, I'd like someone to post a confirmation that the 2002 manual is right about adb and xd commands that follow:
# xd -j8200 -N16 -tu /dev/rdsk/c3t0d0
0000000 0 0 0 0
0000010
# echo "0d8200?DY" | adb /dev/dsk/c3t0d0
2008: 0 1970 Jan 1 01:00:00
# hostname
WWYY
_______________________________________________
_______________________________________________

# echo "0d8200?DY" | adb /dev/dsk/c51t0d0
2008: 0 1970 Jan 1 01:00:00

# xd -j8200 -N16 -tu /dev/rdsk/c51t0d0
0000000 0 0 0 0
0000010

# hostname
JJKK

vgscan failed saying that there's no LVM data , at least on one of the systems.

Literally:
Physical Volume "/dev/dsk/c3t3d7" contains no LVM information

Is there any command to issue in a SAN environment that can help to distinguish among same size LUNs ??!?!?!?

Thanks everybody,
Marco

[FERRARI MARCO]

vgscan said there was no LVM info on the disk.
vgimport confirmed.
pvcreate succeded as well.
I will test the two exoterical commands I quoted in the same or another test environment.
As it was a test environment, a restore from a backup was the favourite way to restart.
Thanks everybody and ....
long live the storage 'expert' who scratched everything !