Procedure for Adding logical volumes to volume groups for Oracle9i RAC

[Prakash_10]

Hello,

Does any know the procedure for adding logical volumes to existing volume groups used by
Oracle9i Real application clusters?. I am working on HP-UX11i/Oracle9i RAC 9.2.0.1

Thanks for all your help.

[Jeff Schussele]

Hi Prakash,

First check for free space in the volume group

vgdisplay /dev/vg_name

Your looking for Free PE to have some value.
If some free space available then create a new logical volume

lvcreate -n lv_name /dev/vg_name

Then create the new filesystem to use that LV

newfs -F vxfs /dev/vg_name/rlv_name (Note that you must use the "raw" volume name

Now create the mount point

mkdir /path/to/mnt_point

then mount it

mount /dev/vg_name/lv_name /path/to/mnt_point

Then edit /etc/fstab so that it will mount at boot time. Add the following to the file

/dev/vg_name_/lv_name /path/to/mnt_point vxfs options 0 2

Note options are the FS options such as delaylog datainlog suid largefiles, etc
do a man mount_vxfs for the entire list.

Now if you DON'T have free space then you'd have to add the new disk to the VG first

Init the disk

pvcreate -f /dev/rdsk/cxtydz (BE CAREFUL that the disk is not already in use in another VG)

Add it to the VG

vgextend /dev/vg_name /dev/dsk/cxtydz

Then you can do the steps as above.

HTH,
Jeff

[Prakash_10]

Hello Jeff,

Thanks for the quick response.

After adding the logical volume to the volume group we could see it on the primary node where we created it. However we are not able to see the logical volume ( vgdisplay) on the other node.

So how do we really get to see the new logical volume on the other node?.

When we activate the volume group on the second node , it just says that is a client and that the group is activated.

Thanks once again for all your help.

Regards

Prakash

[Brian Crabtree]

With RAC, the volume group needs to be mounted exclusively to create the lvol, then exported from the current system, and imported into the other systems. Something like the following should work for you (assuming vgRAC as the volume group, and a 200m lvol named lv_newtbs).

----
vgchange -a e /dev/vgRAC
lvcreate -L 200 -n lv_newtbs /dev/vgRAC
vgchange -a s /dev/vgRAC
vgexport -s -p -v -m vgRAC.map /dev/vgRAC
----

Then move the vgRAC.map file to your other nodes, and run something like the following.

----
vgexport -s -v -m vgRAC.bak /dev/vgRAC
mkdir /dev/vgRAC
mknod /dev/vgRAC/group c 64 0x030000
vgimport -s -v -m -p vgRAC.map /dev/vgRAC
vgchange -a s /dev/vgRAC
----

This should allow you to create the volume group on the secondary system. However, you will want to get the correct minor number (0x030000) from your group file before the vgexport, as must be unique for the local system, although does not require to be the same as on the original system.

Hope this helps,

Brian