Adding a physical disk to a existing volumgroup in MC/SG

[Klaas D. Eenkhoorn]

All,

We have few questions about adding a phisical disk with an alternate hardware path to an existing volumegroup on a 2 node MC/SG cluster.

1) Do we have to take the package with the volumegroup offline and activate the volumegoup manually to add this disk or can it be done on-line ?

2) If we add the disk with vgextend -g datavg_01 /dev/datavg /dev/dsk/c1d0t0 /dev/dsk/c2d0t0 do i have to do this on the 2nd node also ?

3) Do we have to perform pvcreate on the new disks ?

Kl@@s

[John Palmer]

1) No, it can be done online.

2) No, but you'll need to export the VG on the 2nd node and reimport it to get /etc/lvmconf correct. You'll also have to do this if you create any new logical volumes in the VG. This can be done online.

3) Yes

[Marco Santerre · Accepted solution]

Here is a quick procedure I usually use to add disks in a VG

1) on primary :

pvcreate -f /dev/rdsk/c58t0d3

2) vgextend vg01 /dev/dsk/c58t0d3
3) vgexport -p -s -m /tmp/vg01.map vg01
4) rcp /tmp/vg01.map node2:/tmpd11:/tmp
5) cmhaltpkg dbPRD
6) on secondary node :
vgexport vg01
7) mkdir /dev/vg01
8) mknod /dev/vg01/group c 64 0x010000
9) vgimport -s -m /tmp/vg01.map vg01
10) vgchange -c n vg01
11) vgchange -a y vg01
12) vgdisplay -v vg01
13) IF YOU HAVE TIME :
vgchange -a n vg01
cmrunpkg -n node2 pack1
cmhaltpkg pack1
14) on primary node :
cmrunpkg pack1

As you can see, I never stop the package up until the step 5, and I only do so cause I will import my VG on the secondary node. Step 10 to 12 is only verification to make sure the disk I added shows up on my VG on my secondary node. Step 13 is also more verification for my package to make sure it does come up and at the asme time, it is a test for my switch cause I never get enough time to perform real switching tests.

[Klaas D. Eenkhoorn]

1)What would be the command order to do this ?

2)Do we have to remove the volumegroup configuration on the second node first before importing the volumegroup ?

[John Palmer]

On Primary...

pvcreate
vgextend
lvcreate (possibly)
vgexport -m map -s -p
rcp map to Secondary

On Secondary:
vgexport
mkdir -m 755 /dev/
mknod /dev//group c 64 0x??0000
chmod 640 /dev//group
vgimport -m -s -v

Should do. This can all be done without closing any package (or the cluster).

Regards,
John