lvm

[Bill Lawler]

While configuring a new server, I trashed the boot area on the boot disk. I have a nearly identical system that had a mirrored boot disk.

I took the mirrored disk from the working system and put it into the server I trashed. I can now boot up in single user mode on the disk I added.

I cannot get the lvm information correct. If I rename /etc/lvmtab and do a vgscan -v, the new /etc/lvmtab is empty (i.e. no vg00).

vgdisplay vg00 shows it has Cur PV = 2, and Act PV = 1. ioscan data looks good.

pvdisplay /dev/dsk/c1t15d0 (disk from other system that I booted on) returns:
Warning: couldn't query physical volume "/dev/dsk/c3t15d0". The specified path does not correspond to physical volume attached to this volume group. It also shows the pv data for c1t15d0.

pvdisplay /dev/dsk/c3t15d0 returns: Warning: couldn't query physical volume "/dev/dsk/c3t15d0"; The specified path does not correspond to physical volume attached to this volume group. Couldn't query all of the physical volumes. Couldn't retrieve the names of the physical volumes belonging to "/dev/vg00". Cannot display physical volume "/dev/dsk/c3t15d0".

c3t15d0 used to be c1t15d0 on this system.

I've tried various incantations of vgreduce, vgscan, lvextend, etc, but haven't gotten the right order.

What do I need to do?

[Patrick Wallek]

Take your Ignite/UX make_tape_recovery tape, put it in the tape drive, boot the system from the tape, and restore.

[Sridhar Bhaskarla]

Hi Bill,

There are two issues.

1. System that you trashed

Since you booted from the mirror disk of another system, lvmtab would be wrong as well it would be expecting to see another disk. So, we need fix the lvmtab and remove the reference to the other disk

2. System that is missing the mirror disk because you stole it.

You need to put a new disk in the mirror slot. Then you need to restore the PV structures onto the new disk and reestablish the mirroring.


Let us fix 2 as it is simple.

2. Refill the mirror slot using another similar disk (c3t15d0?) and run the following commands.

#mkboot -l /dev/dsk/c3t15d0
#vgcfgrestore -n vg00 /dev/rdsk/c3t15d0
#vgchange -a y vg00
#mkboot -a "hpux -lq" /dev/rdsk/c3t15d0
#vgsync vg00
#lvlnboot -R
#lvlnboot -v (make sure boot, root, swap and dump volumes show up)

#vgdisplay -v (make sure you don't get any errors)

If everything is fine, then take a make_tape_recovery tape. You can use it as PlanB to fix the trashed system if the following does not work.

1.

Move the lvmtab back.
Boot in LVM maintenance mode using the mirror disk of other system (c1t15d0) (Interact with bootadmin and type hpux -lm). Let us say you have another disk say c2t15d0 on this system that was intended to be the mirror for the disk that you trashed.

Once you are LVM maintenance mode, do the following

# vgcfgrestore -f /etc/lvmconf/vg00.conf /dev/rdsk/c2t15d0 (other disk)
#vgexport vg00
#mkdir /dev/vg00
#mknod /dev/vg00/group c 64 0x000000
#vgimport -v vg00 /dev/dsk/c1t15d0 /dev/dsk/c2t15d0
#vgchange -a y vg00
#pvdisplay -v /dev/dsk/c2t15d0 (note down all the lvols)
#lvreduce -m 0 /dev/vg00/lvol1 /dev/dsk/c2t15d0
(repeat the same for other lvols)
#pvdisplay -v /dev/dsk/c2t15d0
(make sure there are no lvols)
#vgreduce vg00 /dev/dsk/c2t15d0
#lvlnboot -b /dev/vg00/lvol1
#lvlnboot -r /dev/vg00/lvol3
#lvlnboot -s /dev/vg00/lvol2
#lvlnboot -d /dev/vg00/lvol
#lvlnboot -v
(make sure everything shows up)


Reboot the box and it should come up.

If you cannot get it working, then use the make_tape_recovery tape of the other system and build it.

-Sri

[Bill Lawler]

1 # vgcfgrestore - /etc/lvmconf/vg00.conf /dev/rdsk/c2t15d0 (other disk)
2 #vgexport vg00
3 #mkdir /dev/vg00
4 #mknod /dev/vg00/group c 64 0x000000
5 #vgimport -v vg00 /dev/dsk/c1t15d0 /dev/dsk/c2t15d0
6 #vgchange -a y vg00
7 #pvdisplay -v /dev/dsk/c2t15d0 (note down all the lvols)
8 #lvreduce -m 0 /dev/vg00/lvol1 /dev/dsk/c2t15d0
(repeat the same for other lvols)
9 #pvdisplay -v /dev/dsk/c2t15d0
(make sure there are no lvols)
10 #vgreduce vg00 /dev/dsk/c2t15d0
11 #lvlnboot -b /dev/vg00/lvol1
12 #lvlnboot -r /dev/vg00/lvol3
13 #lvlnboot -s /dev/vg00/lvol2
14 #lvlnboot -d /dev/vg00/lvol
15 #lvlnboot -v
(make sure everything shows up)

Steps 1 thru 7 went ok with one small hiccup, I received very funny output at one point. I restarted and it seemed to be ok.

On step 8, I receive error: Physical extents on remaining physical volumes are stale or remaining physical volumes are not responding.
lvreduce: The LVM device driver failed to reduce mirrors on the logical volume "/dev/vg00/lvolX".

What do I want to do at this point? Should I sync the mirrors?

[Ross Zubritski]

Try this:

#vgchange -a y vg00
vgsync vg00
#lvlnboot -R
#lvlnboot -v
#vgdisplay -v (make sure you don't get any errors)

Regards,

RZ

[pap]

Hi You can do following :

1.boot from the disk you replaced form another system. ( you already did )
2. pvcreate -B /dev/rdsk/dis_alreay_on_system
3. vgextend /dev/vg00 /dev/dsk/disk_alreay_on_system
4. mv /etc/lvmtab /etc/lvmtab.org
5. vgscan -v

you should now see both disks in the vg00.

do pvdisplay -v /dev/vg00
if it runs successfully, then do mirroring for the root disk as Shridhar suggested.

Hope this works.

Thanks,

-pap

[Darren Prior]

Hi Bill,

I'd seriously consider using the Ignite recovery tape as suggested previously. It is not supported to move boot disks between machines - nearly identical may not be good enough.

regards,

Darren.

[Sridhar Bhaskarla]

Hi,

I got a minute finally to get back to forums.

Though it is not supported by HP (HP says it does not support many things), you can move mirror disks provided you do not hardcode the path in auto string as well you know what you are doing.

Go ahead and do a vgsync and see if it works. Otherwise, restore OS using the ignite tape as I indicated as planB.

-Sri

[Bill Lawler]

I can now boot up, but the disks are still not right.

The kernel thinks the external DVD-ROM is part of vg00.

lvmtab shows:
/dev/vg00
/dev/dsk/c1t15d0

vgscan -v returns:
The physical volume "/dev/dsk/c1t15d0" is already in the /etc/lvmtab file.
Couldn't stat physical volume "/dev/dsk/c2t1d0": invalid argument.

vgcfgrestore: Couldn't query physical volume "/dev/dsk/c3t15d0":
the specified path does not correspond to physical volume attached to this volume group.
Volume Group configuration has been restored to /dev/dsk/c1t15d0

c2t1d0 is the DVD-ROM.

Forum pages on this situation are not much help.

Looks like I get to reinstall, Thanks for the help.

[Sridhar Bhaskarla]

Hi,

You didn't need to run vgcfgrestore and vgscan again once you could be able to boot.

Do a vgchange -a y vg00 . Then do a vgdisplay -v vg00 and see if it gives without any error.

Also, post your lvdisplay -v /dev/vg00/lvol1.

-Sri