Problem with the mirror

[R.K. #]

Hi Jakob,

>> Cannot restore Physical Volumes /dev/dsk/c5t1d0
Need to do "pvchange -a n "

>> same and on the same LE
If this is the case, why not perform write test as mentioned by Viktor. (You already did read test that came up fine). But that will destroy other mirrors.

Another experiment that you can do is un-mirror all LVs in c5t1d0 and re-mirror them, changing ORDER of mirroring this time. So we can see if the same LE (xyz) gets stale or same LV (lvora10g) gets satle extent.

As far as I know, sometimes in rare cases LVM looks as if stale extent is in disk1 (from lvdisplay) whereas it comes out to be in disk2 (not shown in lvdisplay).

All the best..

[R.K. #]

Hi Again..

Take an example of two mirrored disks c4t0d0 and c5t0d0..

There are some stale PE in one disk c4t0d0, but it's not necessary that the disk c4t0d0 is faulty. It's only mean LVM can't sync the data in the mirrored PEs, the 'current' PE has the latest data, the 'stale' PE has old data. The 'current' PE maybe bad such as can't be read from it, then sync failed.

To find the fault disk, we can use dd on each disk, if the disk has I/O error, it's the faulty disk.

# dd if=/dev/dsk/c4t0d0 of=/dev/null bs=1024k
# dd if=/dev/dsk/c5t0d0 of=/dev/null bs=1024k

And some hardware log such as EMS will show error message. In this case, Media failure happened in the 'current' disk.
Check /var/opt/resmon/log/event.log file:

Now, we know that the disk c5t0d0 with 'currect' status is bad. If we use normal procedure to replace disk c5t0d0 in mirror, lvreduce c5t0d0 will fail because c4t0d0 has stale PE and c5t0d0 is current.

There is a tool named lvunstale which can help us to change the stale state.

It will switch which mirror copy is stale. Now, we can replace the bad disk as per normal process.

[JakobK]

Hello,

i have reduce the mirror of all LV and then
i have lvextend the mirror new,started with lvora10g. The result was successful.
Before, i have made the dd of c4t0d0 and this dd did not come back and can't kill -9.
--> reboot and all okay.

(only Infomation: on the oldsyslog i has found the mesg 037 vx_metaioerr on lvora10g)

Many thanks. Merry Christmas!

Yours sincerely
Kati

[JakobK]

Thanks