Split mirror for two servers' own use

[Wei Gao]

Hi All,
I'm having a trouble to do the following:
I have a two node cluster with Service Guard. There are some shared VGs between these two node. The shared VGs are located in external SC-10s and
both servers have access. The hardware pathes are all the same.
I'm trying to split the nodes to create two standalone machine with the same data set
for separated testing.
How should I do it?
Thanks

Wei

[JACQUET]

Hi,

If you want to stop completely your Cluster,
1?) Stop MC/SG services on all node
2?) Export respectively only VG on each node you don't want them to appear at boot, i.e :
Suppose you've got 3 shared vg, vg01,vg02,vg03
- if node A needs to see only vg01, and node B only vg02 and vg03,
do a vgexport of vg02 and vg03 on node A
and a vgexport of vg01 on node B
(for sure, after unmounting FS on thoses VG,...)
3?) You have to deactivate VG on all node and change the shared options :
on node A :
vgchange -c n /dev/vg01
vgchange -a y /dev/vg01
on node B
vgchange -c n /dev/vg02
vgchange -a y /dev/vg02
vgchange -c n /dev/vg03
vgchange -a y /dev/vg03

In this case, you'll have VG on each node not in shared configuration, but both 2 nodes see PV... It can be a bit dangerous, you have to take care of it !!!

Hope it helps...

PJA.

[linuxfan]

Hi Wei,

Your question isn't very clear. Do you want both the nodes to see the shared VGs at the same time? Are the LVs in each of the VGs mirrored? when you split the mirrors and mount them on each node, do you want both the nodes to be able to write to each of these filesystems?

-Ramesh

[Wei Gao]

Hi All,
Thanks for your help. But What I'm trying to do is that
the shared vg, like vg02, after split, each node will have one piece.

Server A: vg02:
disk 4 mirror to disk 5.
Server B: same as server A
with the same H/W path.

Objective:
After split
Server A: vg02: disk4
Server B: vg02: disk5

Thansk.

[Deshpande Prashant]

Hi
If you have Mirror, then you can split it and use one copy on each machine.
Server A
vgchange -c n /dev/vg02
cmhaltcl
vgchange -a y /dev/vg02
mount /dev/vg02/lvol1
lvsplit /dev/vg02/lvol1 # this will get rid of disk5
vgreduce /dev/vg02

On Server B
vgimport /dev/vg02 disk5
vgchange -a y /dev/vg02
fsck /dev/vg02/lvol1
mount /dev/vg02/lvol1


You might be required to do vgchgid on disk5 before importing it on Server B.
I had done similar thing with EMC disks and BCVs.

Thanks.
Prashant