Red Hat GLOBAL FILE SYSTEM 5.0, Руководство администратора

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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
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.
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 Appendix B, The LVM Configuration Files .
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
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