I need help with this particular BC backup scenario

[José Enrique González]

Hi:

I have an MC/SG cluster with three nodes all conected to an XP512, with database LUN's configurated with BC. One of this is a backup and also a stand-by node, so I need to create LVM structures for both primary and BC LUNs. The man page for vgchgid says I should use this command to put a diferent VGID on BC LUNs in order to vgimport then. But it can only be done in disks not included in a volume group in the system where the command is issued from.

Without using vgchgid command I am able to vgimport all primary and BC volume groups. However, after some activation and deactivations, a vgchange -a s hangs, May be this becsuse of both groups with the same VGID in disks?

If I have both primary and BC volume groupos created in this nodo ¿Is it necessary to export/import BC VG's each time I want to backup them, as this is the only way to vgchgid the disks?

Thanks a million in advance for your comments about this

[Sridhar Bhaskarla · Accepted solution]

Hi,

I dont' see a reason why you have to import your primary VG. If you need to, you don't have to chance the vgid for the primary VG.

But if you want to import the BC disks, you will have to change the VGID on them. Otherwise, serviceguard will get confused as it will get the same VGID from two different minor numbers.

To run 'vgchgid' you will have to specify all the disks corresponding to that VG in the *SAME* command. You must not split them or miss them.

-Sri

[Sundar_7]

Hi,

Yes you are right.

If the node is supposed to have both primary and BC volumes mounted at the same time, your typical backup process could look like this

1) umount the logical volumes and deactivate the BC volume group
2) export the BC volume group
3) establish with the primaru
4) Split the BC from the primary
5) run the vgchgid on all the BC volumes
6) vgimport
7) mount the lvs
8) start the backup

- Sundar

[José Enrique González]

Thank you, Sundar, for confirming my suspects. It is a bit complicated as you have to maintain the list of raw volumes to vgchgid them, but can work fine.