topic Re: Lvsplit in Operating System - HP-UX

Lvsplit

Mike_305 — Tue, 13 Nov 2001 01:08:18 GMT

Hi,

I need to split primary copy of mirror and leave secondry.

Thanks in advance.

Mike

Re: Lvsplit

Animesh Chakraborty — Tue, 13 Nov 2001 01:22:08 GMT

Hi,
If you want to split the logical volume
#lvsplit /dev/vg00/lvolx
# fsck /dev/vg00/lvolxb
#mount /dev/vg00/lvolxb /xyz.backup

Remove mirror copies of logical extents of a logical volume from the
physical volume /dev/dsk/c1t0d0:

#lvreduce -m 0 /dev/vg01/lvol4 /dev/dsk/c1t0d0

best of luck
Animesh

Re: Lvsplit

Scott Van Kalken — Tue, 13 Nov 2001 01:25:58 GMT

lvsplit /dev/vg00/lvol4
Logical volume "/dev/vg00/lvol4b" has been successfully created with
character device "/dev/vg00/rlvol4b".
Logical volume "/dev/vg00/lvol4" has been successfully split.
Volume Group configuration for /dev/vg00 has been saved in /etc/lvmconf/vg00.con
f

that's for /tmp

I could now mount the lvol4b

To remerge them:

lvmerge /dev/vg00/lvol4b /dev/vg00/lvol4
Logical volume "/dev/vg00/lvol4b" has been successfully merged
with logical volume "/dev/vg00/lvol4".
Logical volume "/dev/vg00/lvol4b" has been successfully removed.
Volume Group configuration for /dev/vg00 has been saved in /etc/lvmconf/vg00.con
f

...and straight from the man page:
Split an online logical volume which is currently mounted on /usr so
that a backup can take place:

lvsplit /dev/vg00/lvol1
fsck /dev/vg00/lvol1b
mount /dev/vg00/lvol1b /usr.backup

Perform a backup operation, then:

umount /usr.backup
lvmerge /dev/vg00/lvol1b /dev/vg00/lvol1

Scott.

It's lots of fun to do, but not fun when you're fresh faced and everything is shiny new and you realise you've installed a system and mirrored something other than lvol1 first.

Re: Lvsplit

Mike_305 — Tue, 13 Nov 2001 01:28:23 GMT

Hi Animesh,

I am trying to split PE1 and make my PE2 as primary copy. The way you are saying that will not help because the minute I split copy my secondary goes away and primary stays.
I want keep PE2 as online copy.

Thanks in advance

Thanks,

Mike

Re: Lvsplit

Scott Van Kalken — Tue, 13 Nov 2001 01:31:22 GMT

Mike,

Just out of interest, why?

Scott.

Re: Lvsplit

Mike_305 — Tue, 13 Nov 2001 01:39:40 GMT

Hi Scott,

Because on this one logical volume group(disk) my PE1 status is "stale". What I am trying to do is split the primary mirror copy, then do lvreduce on that disk and lvextend back with the same disk. I am also trying to avoid downtime. My database will be running on a mirror copy. I have looked at all the options and I can't get the right answer. Hopefully someone has the answer.

Thanks for your quick reply.

Thanks,

Mike

Re: Lvsplit

Scott Van Kalken — Tue, 13 Nov 2001 01:41:46 GMT

Technically a split and merge should fix this.

Re: Lvsplit

Animesh Chakraborty — Tue, 13 Nov 2001 01:43:29 GMT

Hi Mike,
What are you spliting? the mirror or lv ?

In case of of lvsplit ,you can use the /xyz.backup file system and rename the mount point as required and umount the original one.
Still not sure why you want that way !!

Re: Lvsplit

Animesh Chakraborty — Tue, 13 Nov 2001 01:55:37 GMT

Now it is clear.

Try
#lvchange -a y /dev/vgxx/lvolx

Re: Lvsplit

Animesh Chakraborty — Tue, 13 Nov 2001 02:02:21 GMT

Hi Mike,
Did you try lvsync ?
#lvsync /dev/vgxx/lvolx

Sorry for my splitted replies :)
Animesh

Re: Lvsplit

Sanjay_6 — Tue, 13 Nov 2001 02:50:37 GMT

Hi Mike,

Take a look at the threads below,

http://us-support.external.hp.com/cki/bin/doc.pl/sid=a0a8afd118d1ef8d9e/screen=ckiDisplayDocument?docId=200000054599402

http://us-support.external.hp.com/cki/bin/doc.pl/sid=a0a8afd118d1ef8d9e/screen=ckiDisplayDocument?docId=200000048194460

Hope this helps.

Regds

Re: Lvsplit

James R. Ferguson — Tue, 13 Nov 2001 02:50:52 GMT

Hi MIke:

Under normal conditions, that is all extents in all physical volumes of a mirrored logical volume are current, then 'lvsplit' is used to create an unmirrored copy which can be used for backup purposes, for instance.

Under normal conditions, if you simply want to eliminate a mirrored logical volume, one uses 'lvreduce -m 0 /dev/vgXX/lvolN /dev/dsk/cXtYdZ'. This specifies the physical volume on which you no longer want the mirror.

In the case you report, you have "stale" extents. This may mean a faulty disk. It may also indicate a temporary situation following a power-failed disk event. Thus, 'lvsync' or 'vgsync' is approriate.

Regards!

...JRF...

Re: Lvsplit

James R. Ferguson — Tue, 13 Nov 2001 03:00:30 GMT

Hi Mike:

In the event that an 'lvsync' or 'vgsync' does not return your stale extents to "current", have a lool at Technical Knowledge Base document #KBRC00002271 for further help troubleshooting stale mirrors (attached).

Regards!

...JRF...

Re: Lvsplit

Mike_305 — Tue, 13 Nov 2001 15:18:39 GMT

Hi James,

James has hit the jackpot. I got my answer and works like fine. I wanted to split first copy of mirror and I was able to do that using his recommendation.

Lvdisplay ???v ???k /dev/vg00/lvolx (to find out mirror PV number) then do

Lvreduce ???m 0 /dev/vgXX/lvolN /devdsk/cXtYdZ

Thanks to all of you for your quick reply and help.

Thanks,

Mike