need to replace bad disk in mirror

[William Capen]

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

[TTr]

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]

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

[Vihang.]

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]

Shalom,

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

SEP

[William Capen]

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]

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

[TTr]

> "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]

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.]

>>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...

[Deepak Kr]

William,

Once you replace the faulty disk successfully, follow these steps:

#ioscan -funC disk|more
new disk should recognised here!!

#pvcreate -f -B /dev/rdsk/c_t_d0

#vgcfgrestore -n vgname /dev/rdsk/c_t_d0

# vgchange -a y /dev/vgname

# vgsync vgname

check mirror status after vgsync is completed!!

[Torsten.]

@Kumar Deepak

why using "pvcreate -B ..." on a non-boot disk?

[William Capen]

Are we using the same device name? The dead device is c4t4d0 so the restore should be done to the same device or should I look for a new one?

[Patrick Wallek · Accepted solution]

The device file name should be the same.

If it is not currently showing up in ioscan, then what you should do is:

1) Replace the disk
2) ioscan -fnC disk
to make sure you see it. If the device file names are not showing up, then do
2a) insf -eC disk
to create the device files
2b) ioscan -fnC disk
to make sure the device files are now showing up in ioscan
3) pvcreate
4) vgcfgrestore
5) vgchange -a y vg??
6) vgsync

[Torsten.]

With hp-ux 11.23 and a plain SCSI controller the device file will remain the same.

This could be different with 11.31 or SAS controllers, but you don't have this.

[Deepak Kr]

sorry for typo:

why using "pvcreate -B ..." on a non-boot disk?

pvcreate -f disk

[Torsten.]

Even this is not needed.

The "-f" is dangerous, if you use a wrong disk device file by accident.

The vgcfgrestore will do the same and more as the pvcreate - so pvcreate is not needed.

;-)

[William Capen]

so once I run

ioscan -fnC disk
and
insf -eC disk

and the new device is seen by the system, I only need to do

vgcfgrestore -n vg01 /dev/rdsk/c4_t4_d0

vgchange -a y /dev/vg01

vgsync vg01

That's it?

[Patrick Wallek]

Yep, that should work.

[William Capen]

YEA!!!!! I'm back! That was very scary due to the extreme importance of the file system but it worked! Thanks to ALL of you for your help!

Bill