LVM mirroring for Veritas Oracle RAC?

[Fan Jiang]

Does anyone know if you can do disk migration using Veritas Volume Manager mirroring in a 2 node Veritas Storage Foundation for Oracle Real Application Clusters (Oracle RAC) environment?
My concern is that both of the nodes are active on the same disks, which one to use to run the mirroring process.

Thanks.

[Fan Jiang]

Does anyone know this?

[Steven E. Protter]

You can use mirroring technology, mirror/ux for example to migrate Oracle products, binaries and data.

You can mirror binaries when they are hot, as in being used, though you have a lower risk doing it while the isntallation is down.

As far as oracle data, I've managed to mirror data and then split the data and try and work with it. That procedure is not supported by oracle.

Procedure:

lvtextend -m 1 /dev/vg01/lvvolrac /dev/dsk/c1t1d0

If you have the space, the mirror copy can be on the same disk. I'd recommend a scratch disk.

lvsplit /dev/vg01/lvolrac

splits the mirror and lets you work with the copy for migration purposes.

SEP

[Geoff Wild]

Actually, if you are using VXVM, the correct command is:

vxmirror


Mirroring a disk

To mirror volumes on a disk or control default mirroring and causes a disk to have its contents mirrored to available space on another disk.

Note: Root disk mirroring is supported on HP-UX 11i Version 1.5 only.
vxmirror -g disk_group -d yes|no disk_name [new_disk_name]

vxmirror -d yes disk_name

Option 6 in the vxdiskadm menu performs this task.


Rgds...Geoff

[Fan Jiang]

Thanks guys for the reply. I know how to use either VxVM or HP-UX LVM mirroring. What I am concerned is the Oracle RAC. It is a true active active cluster, which means both nodes have the VGs imported and writes to them with a locking mechanism. If I want to use mirroring to migrate disks to new disks, on which node should I perform this task (mirror and break mirror)? How do I let the other node know this change? Or is this possible at all?

[Jitao Yin_2]

First of all, it can be done. If you are using VxVM, you should do this mirroring from the master node of the clustered VM. There is a clustered vxconfigd running among the nodes in a cluster. At any time, only one master node controls the changes to the VM config. All commands which change the volume configuration should be run from this master node.

The command to determine the master node is:

vxdctl -c mode

Let me know if this works for you.

Jitao Yin