Provided by: lvm2_2.02.133-1ubuntu10_amd64 bug

NAME

       lvmetad — LVM metadata cache daemon

SYNOPSIS

       lvmetad  [-l  level[,level...]]  [-p pidfile_path] [-s socket_path] [-t
       timeout_value] [-f] [-h] [-V] [-?]

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 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:
       lvm.conf(5) global/use_lvmetad

       For more information on this setting, see:
       lvmconfig --withcomments global/use_lvmetad

       To ignore disks from LVM at the system level, e.g. lvmetad, pvscan use:
       lvm.conf(5) devices/global_filter

       For more information on this setting, see
       lvmconfig --withcomments devices/global_filter

OPTIONS

       To run the daemon in a test environment both the pidfile_path  and  the
       socket_path should be changed from the defaults.

       -f     Don't fork, but run in the foreground.

       -h, -? Show help information.

       -l levels
              Specify  the  levels  of  log  messages  to  generate as a comma
              separated list.  Messages are logged by  syslog.   Additionally,
              when -f is given they are also sent to standard error.  Possible
              levels are: all, fatal, error, warn, info, wire, debug.

       -p pidfile_path
              Path to the pidfile. This overrides both  the  built-in  default
              (/run/lvmetad.pid)      and     the     environment     variable
              LVM_LVMETAD_PIDFILE.  This file is used to prevent more than one
              instance of the daemon running simultaneously.

       -s socket_path
              Path  to  the  socket  file.  This  overrides  both the built-in
              default (/run/lvm/lvmetad.socket) and the  environment  variable
              LVM_LVMETAD_SOCKET.   To  communicate successfully with lvmetad,
              all LVM2 processes should use the same socket path.

       -t timeout_value
              The daemon may shutdown after being idle for the given time  (in
              seconds).  When the option is omitted or the value given is zero
              the daemon never shutdowns on idle.

       -V     Display the version of lvmetad daemon.

ENVIRONMENT VARIABLES

       LVM_LVMETAD_PIDFILE
              Path for the pid file.

       LVM_LVMETAD_SOCKET
              Path for the socket file.

SEE ALSO

       lvm(8), lvmconfig(8), lvm.conf(5), pvscan(8)