D.3. Controlling Activation with Tags
You can specify in the configuration file that only certain logical volumes should be activated on that host. For example, the following entry acts as a filter for activation requests (such as
vgchange -ay
) and only activates vg1/lvol0
and any logical volumes or volume groups with the database
tag in the metadata on that host.
activation { volume_list = ["vg1/lvol0", "@database" ] }
There is a special match "@*" that causes a match only if any metadata tag matches any host tag on that machine.
As another example, consider a situation where every machine in the cluster has the following entry in the configuration file:
tags { hosttags = 1 }
If you want to activate
vg1/lvol2
only on host db2
, do the following:
- Run
lvchange --addtag @db2 vg1/lvol2
from any host in the cluster. - Run
lvchange -ay vg1/lvol2
.
This solution involves storing hostnames inside the volume group metadata.