mirror of
git://sourceware.org/git/lvm2.git
synced 2024-12-22 17:35:59 +03:00
115 lines
3.4 KiB
Groff
115 lines
3.4 KiB
Groff
.TH LVMETAD 8 "LVM TOOLS #VERSION#" "Red Hat Inc" \" -*- nroff -*-
|
|
.SH NAME
|
|
lvmetad \(em LVM metadata cache daemon
|
|
|
|
.SH SYNOPSIS
|
|
.B lvmetad
|
|
.RB [ \-l
|
|
.RI { all | wire | debug }]
|
|
.RB [ \-p
|
|
.IR pidfile_path ]
|
|
.RB [ \-s
|
|
.IR socket_path ]
|
|
.RB [ \-f ]
|
|
.RB [ \-h ]
|
|
.RB [ \-V ]
|
|
.RB [ \-? ]
|
|
|
|
.SH DESCRIPTION
|
|
|
|
The lvmetad daemon caches LVM metadata, so that LVM commands can read
|
|
metadata without scanning disks.
|
|
|
|
Metadata caching can be an advantage because scanning disks is time
|
|
consuming and may interfere with the normal work of the system and disks.
|
|
|
|
lvmetad does not read metadata from disks itself. The 'pvscan \-\-cache'
|
|
command scans disks, reads the LVM metadata and sends it to lvmetad.
|
|
|
|
New LVM disks that appear on the system must be scanned by pvscan before
|
|
lvmetad knows about them. If lvmetad does not know about a disk, then LVM
|
|
commands using lvmetad will also not know about it. When disks are added
|
|
or removed from the system, lvmetad must be updated.
|
|
|
|
lvmetad is usually combined with event-based system services that
|
|
automatically run pvscan \-\-cache on new disks. This way, the lvmetad
|
|
cache is automatically updated with metadata from new disks when they
|
|
appear. LVM udev rules and systemd services implement this automation.
|
|
Automatic scanning is usually combined with automatic activation. For
|
|
more information, see
|
|
.BR pvscan (8).
|
|
|
|
If lvmetad is started or restarted after disks have been added to the
|
|
system, or if the global_filter has changed, the cache must be updated by
|
|
running 'pvscan \-\-cache'.
|
|
|
|
When lvmetad is not used, LVM commands revert to scanning disks for LVM
|
|
metadata.
|
|
|
|
Use of lvmetad is enabled/disabled by:
|
|
.br
|
|
.BR lvm.conf (5)
|
|
.B global/use_lvmetad
|
|
|
|
For more information on this setting, see:
|
|
.br
|
|
.B lvmconfig \-\-withcomments global/use_lvmetad
|
|
|
|
To ignore disks from LVM at the system level, e.g. lvmetad, pvscan use:
|
|
.br
|
|
.BR lvm.conf (5)
|
|
.B devices/global_filter
|
|
|
|
For more information on this setting, see
|
|
.br
|
|
.B lvmconfig \-\-withcomments devices/global_filter
|
|
|
|
.SH OPTIONS
|
|
|
|
To run the daemon in a test environment both the pidfile_path and the
|
|
socket_path should be changed from the defaults.
|
|
.TP
|
|
.B \-f
|
|
Don't fork, but run in the foreground.
|
|
.TP
|
|
.BR \-h ", " \-?
|
|
Show help information.
|
|
.TP
|
|
.IR \fB\-l " {" all | wire | debug }
|
|
Select the type of log messages to generate.
|
|
Messages are logged by syslog.
|
|
Additionally, when \-f is given they are also sent to standard error.
|
|
Since release 2.02.98, there are two classes of messages: wire and debug.
|
|
Selecting 'all' supplies both and is equivalent to a comma-separated list
|
|
\-l wire,debug.
|
|
Prior to release 2.02.98, repeating \-d from 1 to 3 times, viz. \-d, \-dd, \-ddd,
|
|
increased the detail of messages.
|
|
.TP
|
|
.B \-p \fIpidfile_path
|
|
Path to the pidfile. This overrides both the built-in default
|
|
(#DEFAULT_PID_DIR#/lvmetad.pid) and the environment variable
|
|
\fBLVM_LVMETAD_PIDFILE\fP. This file is used to prevent more
|
|
than one instance of the daemon running simultaneously.
|
|
.TP
|
|
.B \-s \fIsocket_path
|
|
Path to the socket file. This overrides both the built-in default
|
|
(#DEFAULT_RUN_DIR#/lvmetad.socket) and the environment variable
|
|
\fBLVM_LVMETAD_SOCKET\fP. To communicate successfully with lvmetad,
|
|
all LVM2 processes should use the same socket path.
|
|
.TP
|
|
.B \-V
|
|
Display the version of lvmetad daemon.
|
|
.SH ENVIRONMENT VARIABLES
|
|
.TP
|
|
.B LVM_LVMETAD_PIDFILE
|
|
Path for the pid file.
|
|
.TP
|
|
.B LVM_LVMETAD_SOCKET
|
|
Path for the socket file.
|
|
|
|
.SH SEE ALSO
|
|
.BR lvm (8),
|
|
.BR lvmconfig (8),
|
|
.BR lvm.conf (5),
|
|
.BR pvscan (8)
|