topic Re: Booting off Splitted Disk in Operating System - HP-UX

Booting off Splitted Disk

abcd7 — Thu, 05 Apr 2007 04:06:06 GMT

Hi,

If VG00 has 2 disks and if the LVOL's are all 'lvsplt', is it possible to boot off this PV ? ( It is still part of VG00 !! ). Can one
use 'setboot -p' to set this as Primary Boot disk ?

Cheers

Doug

Re: Booting off Splitted Disk

abcd7 — Thu, 05 Apr 2007 21:01:23 GMT

Hi,

COuld you please clarify if I can boot of an 'lvsplit'd disk ?

Thanks

Doug

Re: Booting off Splitted Disk

Jollyjet — Fri, 06 Apr 2007 00:31:40 GMT

Hi,

After splitting the lvol's you need to perform a vgreduce to remove the secondary disk from vg00 after using vgreduce check vgdisplay and confirm whether you secondary disk is listing in vg00 if it reflects the second disk is not properly removed from vg00 if it's not reflecting you can boot the os with the primary disk.

Re: Booting off Splitted Disk

abcd7 — Fri, 06 Apr 2007 04:36:19 GMT

Hi,

I don't think you can VGREDUCE, if the LVOL's still exist on the disk. First you need to an LVREDUCE / LVREMOVE and go for VGREDUCE.

If use any of the above commands, I will be loosing the LVOL info. / data, as well.

Thanks

Doug

Re: Booting off Splitted Disk

IT_2007 — Fri, 06 Apr 2007 09:19:52 GMT

yes. You can do this. Once your work is done then you have to issue lvmerge command.

see man page for lvsplit command.

here it is.......

Split the mirrored logical volume /dev/vg00/lvol1 into two copies.
Call the new logical volume /dev/vg00/lvol1backup:

lvsplit -s backup /dev/vg00/lvol1

Split the mirrored logical volume /dev/vg00/lvol1 into two copies.
The offline logical volume will be created using the mirror copy on
the physical volumes contain in the physical volume group pvg1.

lvsplit -g pvg1 /dev/vg00/lvol1
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

Split two logical volumes at the same time:

lvsplit /dev/vg01/database1 /dev/vg01/database2

Perform operation on split logical volumes, then rejoin them:

lvmerge /dev/vg01/database1b /dev/vg01/database1
lvmerge /dev/vg01/database2b /dev/vg01/database1

WARNINGS
After a two-way mirrored logical volume has been split once, it cannot
be split again without merging the logical volumes using the lvmerge
command (see lvmerge(1M)).

Re: Booting off Splitted Disk

abcd7 — Fri, 06 Apr 2007 20:32:00 GMT

Hi,

Many Thanks for your reply. Well, I'm interested in booting off the system using the LVOL's formed by this splitted disk and not taking a backup.

If it were a storage box like XP / EMC, I'm sure it is possible to form a new VG with splitted LVOL's.

I want to form a new VG with these 'lvsplit'd' LVOL's. Is this possible ?

Thanks

Doug

Re: Booting off Splitted Disk

Zinky — Thu, 19 Apr 2007 09:07:34 GMT

No it is not possible simply with LVM.

The best that you can do is set up an alternate vg00 - vgbak and do a periodic copy (dd of your lvols over).

If your intent for the split bootdisk is to use it for another system with exact same hardware AND that bootdisk is a SAN disk and happens to be "split" via BusinessCOpy or BCV - THEN it is possible.

Re: Booting off Splitted Disk

abcd7 — Sun, 22 Apr 2007 08:21:26 GMT

Thanks to all for your replies. Hope I have awarded points reasonbly.
Closing the thread, but replies are still welcome. I keep checking
it and if possible award points.

BR

Doug