LVM and VxVM

need to replace bad disk in mirror

 
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William Capen
Advisor

need to replace bad disk in mirror

Hi,

I'm running on a rx4640 at 11.23 with all patches installed.

I've been giving a setup that I've not worked with before and it has a bad disk. This is not a system disk.

I have a scsi shelf containing the max of 14 disks. 7 of those disks are mirrored to the other 7. One of the disks is bad. LV status shows available/stale. Thirteen of the disks show up in the Physical volumes list but not the bad one. A listing of Logical extents gives me 2168 lines of
"23868 ??? 02168 stale /dev/dsk/c5t4d0 02168 current"
where the rest of the 25000 lines are currenet/current. So my question is, do I have to remove the mirror before I can replace the one disk or is the disk hot swappable? Or is there anything else I can do? I do not have any slots in which to place another disk prior to the replacement. I also get no response from the bad disk at all.

Thanks,

Bill
19 REPLIES 19
TTr
Honored Contributor

Re: need to replace bad disk in mirror

Take a look at
http://docs.hp.com/en/5991-1236/When_Good_Disks_Go_Bad.pdf
It will tell you how to do it.
Prashanth Waugh
Esteemed Contributor

Re: need to replace bad disk in mirror

Hi William,

before inserting a new disk take the o/p of

#ioscan -fnC disk
Also look in to /etc/lvmtab

That will easy to u after replacing the disk whether its detected or not

Regards
Atul
For success, attitude is equally as important as ability
Vihang.
Trusted Contributor

Re: need to replace bad disk in mirror

Hi William,

You can replace the disk & do a vgcfgrestore. But go through the document which TTR has pointed to. Its a very good document & will give you pretty good insights on how to go about it.


Regards,
Vihang.
Steven E. Protter
Exalted Contributor

Re: need to replace bad disk in mirror

Shalom,

http://docs.hp.com/en/5991-1236/When_Good_Disks_Go_Bad.pdf

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Steven E Protter
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William Capen
Advisor

Re: need to replace bad disk in mirror

I had looked at the PDF which got me to the question of removing the mirror or is the disk hot swappable. ioscan doesn't show the disk but lvmtab does. Doing diskinfo gets me no such device. At this point I can assume that there are no extents on the disk. If I need to remove the mirror, that's a bit of an over kill I think.
Deepak Kr
Respected Contributor

Re: need to replace bad disk in mirror

William,

Can you confirm if disk (14) are mirrored at storage box level or at OS level.

IF at storage box level then procedure will differ here!!

If at OS level then we will use different steps!!

provide vgdisplay -v vg_name
#lvdisplay /dev/vg_name/lv_name |grep mirror
#lvdisplay -v /dev/vg_name/any_lv_name |tail -9

"There is always some scope for improvement"
TTr
Honored Contributor

Re: need to replace bad disk in mirror

> "23868 ??? 02168 stale /dev/dsk/c5t4d0 02168 current

This shows that there is a missing disk that was part of LVM mirroring. The 3 questionmarks above are in place of the missing disk device. The c5t4d0 is the good disk remaining in the mirror setup.
The disk should be hot pluggable. You did not say what kind of enclosure it is but everything nowadays is hot pluggable at least.
William Capen
Advisor

Re: need to replace bad disk in mirror

The enclosure is a 14 disk scsi box filled to capacity. The mirroring is done with LVM. As you can see by the attached there are 24999 lines when doing a lvdisplay. 2168 are telling me that one of the 7 disks in the mirror is no longer with us.

If I understand you correctly, I can just remove the dead disk and insert a new one. At that point I'll need to determine if OLR is installed or not on the system.
Torsten.
Acclaimed Contributor

Re: need to replace bad disk in mirror

>>At that point I'll need to determine if OLR is installed or not on the system

Because you are running 11.23 I assume you have.

man pvchange

if the "-a" option is listed, OLR is available.

You *must* use

pvchange -a n ...

in order to replace the disk, otherwise the vgcfgrestore will not work!

Just follow the well known manual...

Hope this helps!
Regards
Torsten.

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