topic Re: unmirror command in Operating System - HP-UX

unmirror command

JRiggs — Sun, 27 May 2001 14:15:33 GMT

hi,

could anyone guide me on how to do unmirroring on Version 11.0. what are the sequence of commands i should use?

thanks for anyone who can guide me.

Re: unmirror command

A. Clay Stephenson — Sun, 27 May 2001 15:27:44 GMT

Hi Jasper,

To remove a mirror:

Example reduce vg01

1) vgdisplay -v /dev/vg01

This will list the logical volumes under vg01
and also the disks that comprise vg01. I assume that you want to remove the mirrors associated with a physical volume.

For our purposes I'll use vg01 that has lvol01 and lvol02 as an example. The PV disks are c2t5d0 and c3t5d0. We'll pretent to want to remove the mirrors associated with c3t5d0. I also assume that you have 1 mirror copy for each logical volume. We will then set the mirror copies to 0.

2) lvreduce -m 0 /dev/vg01/lvol01 /dev/dsk/c3t5d0
lvreduce -m 0 /dev/vg01/lvol02 /dev/dsk/c3t5d0

This will do it, Clay

Re: unmirror command

A. Clay Stephenson — Sun, 27 May 2001 15:47:36 GMT

Hi Jasper,

After looking at your question again, I realize that I might has answered incorrectly. If you want to actually remove a mirror then the above response is correct. However, if 'unmirror' means to split a logical volume to do a backup then:

1) lvsplit /dev/vg01/lvol01

This will split lvol01 into 2 logical volumes lvol01 and lvol01b. The 'b' suffix is the default but can be changed using the -s argument. Man lvsplit for details

2) lvol01 and its filesystem (e.g. /fs01 )remains mounted.

3) fsck -F vxfs /dev/vg01/lvol01b
(I'm assuming vxfs filesystem type)

4) mkdir /fs01b

5) mount -F vxfs /dev/vg01/lvol01b /fs01b

6) Backup /fs01b using cpio, tar, OB2, etc.

7) Now lets remirror
umount /fs01b
rmdir /fs01b
lvmerge /dev/vg01/lvol01b /dev/vg01/lvol01

Done.

I suggest that you man lvreduce,lvsplit,lvmerge, and perhaps vgreduce for details.

Regards, Clay

Re: unmirror command

JRiggs — Sun, 27 May 2001 18:15:48 GMT

is there any problem if i dont unmirror vg00 when doing ignite for 11? If there is, why?

Re: unmirror command

James R. Ferguson — Sun, 27 May 2001 18:23:15 GMT

Hi Jasper:

There is no need to break any mirror when you run make_tape_recovery (or the older make_recovery). In fact, make_tape_recovery doesn't require any special system state. On a highly active system you may note [from the Ignite release notes]:

"Both make_net_recovery and make_tape_recovery may result in warning messages regarding temporary files that pax was not able to put into the archive. This is due to a design change such that there is a longer period of time between when the list of files to archive are generated and when pax is called."

...JRF...