topic Re: root disk missing? in Operating System - HP-UX

root disk missing?

Mike Boswell_1 — Tue, 22 May 2007 08:42:44 GMT

I have a server hpux 11.0 that has a failed root disk. It is mirrored and hot-swappable. Ioscan does not show the device. Insf -e does not create the dev file. I would like to replace the bad drive. 2 things, are the following steps correct? and how do I vgreduce when there is no device file?

Thanks Mike

1) vgreduce /dev/vg00 /dev/dsk/c2t2d0
2) physically pull out the bad disk and put in the good.
3) mkboot -l /dev/rdsk/c2t2d0
4) mkboot -a "hpux -lq" /dev/rdsk/c2t2d0
5) vgsync vg00

> vgdisplay -v vg00
vgdisplay: Warning: couldn't query physical volume "/dev/dsk/c2t2d0":
The specified path does not correspond to physical volume attached to
this volume group
vgdisplay: Warning: couldn't query all of the physical volumes.
--- Volume groups ---
VG Name /dev/vg00
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 8
Open LV 8
Max PV 16
Cur PV 2
Act PV 1
Max PE per PV 2500
VGDA 2
PE Size (Mbytes) 4
Total PE 2169
Alloc PE 1704
Free PE 465
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

~~~~~~~ cut ~~~~~~~~

--- Physical volumes ---
PV Name /dev/dsk/c1t2d0
vgdisplay: Warning: couldn't query physical volume "/dev/dsk/c2t2d0":
The specified path does not correspond to physical volume attached to
this volume group
vgdisplay: Warning: couldn't query all of the physical volumes.
PV Status available
Total PE 2169
Free PE 465
Autoswitch On

Re: root disk missing?

melvyn burnard — Tue, 22 May 2007 08:45:35 GMT

you do not need to vgreduce.
omit step 1
after installing the new disk, use vgcfgrestore to restore LVM layout to the disc.
Then do the vgsync

Re: root disk missing?

Mike Boswell_1 — Tue, 22 May 2007 08:47:32 GMT

Clarify. Ioscan does not show c2t2d0 but the device file exists in /dev/dsk/ and /dev/rdsk.

Re: root disk missing?

David Child_1 — Tue, 22 May 2007 08:49:09 GMT

1) Pull drive and replace
2) Use vgcfgrestore on the replaced drive
3) vgsync

Re: root disk missing?

David Child_1 — Tue, 22 May 2007 08:51:14 GMT

Sorry, I believe you will need to do a pvcreate -B on the drive before vgcfgrestore. It's been a little while since I've had to replace on.

David

Re: root disk missing?

Patrick Wallek — Tue, 22 May 2007 08:51:24 GMT

After putting the replacing the drive, do an ioscan to verify that it can be seen. You could try doing a diskinfo on the drive to make sure it is accessable.

After that, do the vgcfgrestore as recommended above. I would then do 'vgchange -a y vg00' and then a 'vgsync vg00' to sync all VGs.

Re: root disk missing?

Mike Boswell_1 — Tue, 22 May 2007 09:07:41 GMT

Thanks, Few more questions.

Anyway for me to confirm the vg00.conf file is good?

What about mkboot commands? Will the vgcfgrestore restore those configs ?

Mike

Re: root disk missing?

Mike Boswell_1 — Tue, 22 May 2007 09:50:19 GMT

Patrick,
Why the vgchange? Wouldn't you expect it to already be active? Or does this accomplish something else?

Thanks,

Re: root disk missing?

mavrick — Tue, 22 May 2007 09:59:03 GMT

Hi,
From ypur input the procedure to be followed is
Replace the disk
run
#vgcfgrestore vg00
for restoring the vg details to new disk.
Then create the mkboot
mkboot /dev/rdsk/c2t2d0
mkboot -a "hpux -lq" /dev/dsk/c2t2d0
lvextend -m 1 /dev/vg00/boot /dev/dsk/c2t2d0
similarly root,swap and all other Lvols in your vg00 volume.
Then update the vg00
lvlnboot -R

Re: root disk missing?

Geoff Wild — Tue, 22 May 2007 12:04:30 GMT

For a root disk:

After failed disk has been replaced by HP (assuming the disk is c2t2d0):

vgcfgrestore -n /dev/vg00 /dev/rdsk/c2t2d0

mkboot /dev/rdsk/c2t2d0

mkboot -a "hpux -lq (;0) /stand/vmunix" /dev/rdsk/c2t2d0

vgchange -a y /dev/vg00

lvlnboot -Rv /dev/vg00

vgsync /dev/vg00

1) If the disk is completely "dead", such as if you run ioscan and status is "no_hw" then you can hot swap the disk online.

2) However in circumstances where the disk has not fully failed please do one of the following to avoid data corruption :

a) reduce mirror before replacing the disk
b) deactivate VG before replacing the disk
c) shutdown system to replace the disk

Rgds...Geoff

Re: root disk missing?

Mike Boswell_1 — Tue, 22 May 2007 12:17:15 GMT

Geoff,

I am still wondering why the vgchange? Vg00 will be online during the replacement. c1t2d0, the mirror, will be accessed during the replacement. Will you explain. Also, c2t2d0 does not show at all in ioscan. Would you say its safe to pull out HOT?

Mike

Re: root disk missing?

Geoff Wild — Tue, 22 May 2007 12:24:39 GMT

Yes, you need the vgchange to activate the new disk in the vg.

As far as ioscan, you should see something like:

disk 13 1/0/4/0/0.1.19.0.0.0.0 sdisk NO_HW DEVICE EMC SYMMETRIX
/dev/dsk/c11t0d0 /dev/rdsk/c11t0d0

But if c2t2d0, then it is really gone...

Does the device file show in a ll /dev/dsk/c2t2d0 ?

You may have to do a total re-mirror and may have to do a vgreduce -f

I would try hot swapping it, then run a ioscan -fnC disk and an insf -eC disk

Then see if it shows in your ioscan again...

If yes, then just do the vgcfgrestore commands...

Rgds...Geoff

Re: root disk missing?

Mike Boswell_1 — Tue, 22 May 2007 12:27:14 GMT

Thank you everyone.

Re: root disk missing?

Torsten. — Tue, 22 May 2007 12:57:34 GMT

You are running 11.00 only - but, for newer versions there is a new command (switch):

pvchange -a y|n ...

to (de-)activate the disk for LVM use to make the hot-swap safe, see

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