C.3. Controlling Activation with Tags

C.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:

  1. Run lvchange --addtag @db2 vg1/lvol2 from any host in the cluster.

  2. Run lvchange -ay vg1/lvol2.

This solution involves storing hostnames inside the volume group metadata.


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