[11.11] vg and lvol lost in sam, how to find them?

[Leam Hall]

Okay, sorry for the odd Subject line. The question seems a bit convoluted.

We had some issues and many of our servers were temporarily powered off. When this one came back, one of it's volume groups and the attendant logical volume went missing. They do not show up in sam, though there's no issues reported in "ioscan -fnC disk". The files are still in /dev/vg01/(lvol9|rlvol9|group). If I try to mount it I get:

vxfs mount: Cannot open /dev/vg01/lvol9: No such device or address

The server has some old disk arrays attached. None of the disks are showing error lights. What else can I do to find information?

[Pete Randall]

How about vgscan?


Pete

[Leam Hall]

Also:

vgdisplay vg01
vgdisplay: Volume group not activated.

[Torsten. · Accepted solution]

Lets collect some information:

# strings /etc/lvmtab

Note the disk devices under VG01.

Compare with "ioscan -fn" - are they there?

Try to activate VG01.

If done, do "vgdisplay -v vg01", post the output.

[rariasn]

Hi Leam:

# vgchange -a y vg01

# mount /dev/vg01/lvol9

rgs,

[James R. Ferguson]

Hi:

If you can't activate the volume group as suggested, note the devices cataloged in '/etc/lvmtab' for the group in question. Then see if you can actually access them by doing:

# dd if=/dev/rdsk/cXtYdZ of=/dev/null bs=1024k count=10

Regards!

...JRF...

[Leam Hall]

Ran vgscan, still processing the output. There are actually two failed VGs on this machine, though the other one just seems to have a failed disk.



Here's the snippit from "strings /etc/lvmtab". Note that there are no devices c9tXdX showing up in ioscan.

/dev/vg01
cH=]
/dev/dsk/c4t5d0
/dev/dsk/c9t0d1 no c9tXdX on ioscan -fnC disk
/dev/dsk/c9t0d3 no c9tXdX on ioscan -fnC disk

[Torsten.]

>> /dev/dsk/c9t0d1 no c9tXdX on ioscan -fnC disk
/dev/dsk/c9t0d3 no c9tXdX on ioscan -fnC disk



Since the LUNs are on an array, you need to check the array or the SAN between. Looks like the LUNs are not visible from the host.

[Bill Hassell]

You have lost disk LUNs from your array(s). Although there are no error lights, there are numerous failures including SAN switches that can cause the loss of LUN visibility. When a volume group cannot be activated, start with the very lowest level commands to check on the disks:

ioscan -fC disk
diskinfo /dev/rdsk/cXtYdZ
dd if=/dev/rdsk/cXtYdZ of=/dev/null bs=1024k count=10

Any "NO_HW" or other failures means that the disks are not available and any further commands (like vgscan) will probably hang or fail.

> We had some issues and many of our servers were temporarily powered off.

I am assuming that there was an unexpected power failure and this can cause lots of problems with older disk arrays. You'll need to verify every disk LUN one at a time before trying to activate the VGs.

[Leam Hall]

Well...the dd trick is good to know, but here we've lost the disks it seems. That's what we get for running old hardware.

No worries though, perhaps they'll ante up for some new hardware.

Leam