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Appendix C. LVM Object Tags
An LVM tag is a word that can be used to group LVM2 objects of the same type together. Tags can
be attached to objects such as physical volumes, volume groups, and logical volumes. Tags can be
attached to hosts in a cluster configuration. Snapshots cannot be tagged.
Tags can be given on the command line in place of PV, VG or LV arguments. Tags should be prefixed
with @ to avoid ambiguity. Each tag is expanded by replacing it with all objects possessing that tag
which are of the type expected by its position on the command line.
LVM tags are strings using [A-Za-z0-9_+.-] of up to 128 characters. They cannot start with a hyphen.
Only objects in a volume group can be tagged. Physical volumes lose their tags if they are removed
from a volume group; this is because tags are stored as part of the volume group metadata and that is
deleted when a physical volume is removed. Snapshots cannot be tagged.
The following command lists all the logical volumes with the database tag.
lvs @database
C.1. Adding and Removing Object Tags
To add or delete tags from physical volumes, use the --addtag or --deltag option of the
pvchange command.
To add or delete tags from volume groups, use the --addtag or --deltag option of the vgchange
or vgcreate commands.
To add or delete tags from logical volumes, use the --addtag or --deltag option of the lvchange
or lvcreate commands.
C.2. Host Tags
In a cluster configuration, you can define host tags in the configuration files. If you set hosttags = 1
in the tags section, a host tag is automatically defined using the machine's hostname. This allow you
to use a common configuration file which can be replicated on all your machines so they hold identical
copies of the file, but the behavior can differ between machines according to the hostname.
For information on the configuration files, see
For each host tag, an extra configuration file is read if it exists: lvm_hosttag.conf. If that file defines
new tags, then further configuration files will be appended to the list of files to read in.
For example, the following entry in the configuration file always defines tag1, and defines tag2 if the
hostname is host1.
tags { tag1 { }
Appendix B, The LVM Configuration
tag2 { host_list = ["host1"] } }
Files.
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