C.5. Selection Criteria Processing Examples
This section provides a series of examples showing how to use selection criteria in commands that process LVM logical volumes.
This example shows the initial configuration of a group of logical volumes, including thin snapshots. Thin snapshots have the "skip activation" flag set by default. This example also includes the logical volume
lvol4 which also has the "skip activation" flag set.
# lvs -o name,skip_activation,layout,role
LV SkipAct Layout Role
root linear public
swap linear public
lvol1 thin,sparse public
lvol2 thin,sparse public,origin,thinorigin
lvol3 skip activation thin,sparse public,snapshot,thinsnapshot
lvol4 skip activation linear public
pool thin,pool private
The following command removes the skip activation flag from all logical volmes that are thin snapshots.
# lvchange --setactivationskip n -S 'role=thinsnapshot'
Logical volume "lvol3" changed.
The following command shows the configuration of the logical volumes after executing the
lvchange command. Note that the "skip activation" flag has not been unset from the logical volume that is not a thin snapshot.
# lvs -o name,active,skip_activation,layout,role
LV Active SkipAct Layout Role
root active linear public
swap active linear public
lvol1 active thin,sparse public
lvol2 active thin,sparse public,origin,thinorigin
lvol3 thin,sparse public,snapshot,thinsnapshot
lvol4 active skip activation linear public
pool active thin,pool private
The following command shows the configuration of the logical volumes after an additional thin origin/snapshot volume has been created.
# lvs -o name,active,skip_activation,origin,layout,role
LV Active SkipAct Origin Layout Role
root active linear public
swap active linear public
lvol1 active thin,sparse public
lvol2 active thin,sparse public,origin,thinorigin
lvol3 lvol2 thin,sparse public,snapshot,thinsnapshot
lvol4 active skip activation linear public
lvol5 active thin,sparse public,origin,thinorigin
lvol6 lvol5 thin,sparse public,snapshot,thinsnapshot
pool active thin,pool private
The following command activates logical volumes that are both thin snapshot volumes and have an origin volume of
lvol2.
#lvchange -ay -S 'lv_role=thinsnapshot && origin=lvol2'#lvs -o name,active,skip_activation,origin,layout,roleLV Active SkipAct Origin Layout Role root active linear public swap active linear public lvol1 active thin,sparse public lvol2 active thin,sparse public,origin,thinorigin lvol3 active lvol2 thin,sparse public,snapshot,thinsnapshot lvol4 active skip activation linear public lvol5 active thin,sparse public,origin,thinorigin lvol6 lvol5 thin,sparse public,snapshot,thinsnapshot pool active thin,pool private
If you execute a command on a whole item while specifying selection criteria that match an item from that whole, the entire whole item is processed. For example, if you change a volume group while selecting one or more items from that volume group, the whole volume group is selected. This example selects logical volume
lvol1, which is part of volume group vg. All of the logical volumes in volume group vg are processed.
#lvs -o name,vg_nameLV VG root fedora swap fedora lvol1 vg lvol2 vg lvol3 vg lvol4 vg lvol5 vg lvol6 vg pool vg #vgchange -ay -S 'lv_name=lvol1'7 logical volume(s) in volume group "vg" now active
The following example shows a more complex selection criteria statement. In this example, all logical volumes are tagged with "mytag" if they have a role of origin and are also named lvol[456] or the logical volume size is more than 5g.
# lvchange --addtag mytag -S '(role=origin && lv_name=~lvol[456]) || lv_size > 5g'
Logical volume "root" changed.
Logical volume "lvol5" changed.
