Provided by: gfs2-cluster_3.1.3-0ubuntu1_amd64 bug


       gfs_controld - daemon that manages mounting, unmounting, recovery and posix locks


       gfs_controld [OPTION]...


       GFS  lives  in  the  kernel,  and the cluster infrastructure (cluster membership and group
       management) lives in user space.  GFS in the kernel needs to  adjust/recover  for  certain
       cluster  events.  It's the job of gfs_controld to receive these events and reconfigure gfs
       as needed.  gfs_controld  controls  and  configures  gfs  through  sysfs  files  that  are
       considered gfs-internal interfaces; not a general API/ABI.

       Mounting,  unmounting  and  node  failure  are  the  main cluster events that gfs_controld
       controls.  It also manages the assignment of journals to different nodes.   The  mount.gfs
       and  umount.gfs  programs  communicate with gfs_controld to join/leave the mount group and
       receive the necessary options for the kernel mount.

       GFS also sends all posix lock operations to  gfs_controld  for  processing.   gfs_controld
       manages cluster-wide posix locks for gfs and passes results back to gfs in the kernel.


       Optional cluster.conf settings are placed in the <gfs_controld> section.

   Posix locks
       Heavy  use  of  plocks  can  result  in  high  network load.  The rate at which plocks are
       processed are limited by the plock_rate_limit setting,  which  limits  the  maximum  plock
       performance,  and  limits  potentially  excessive network load.  This value is the maximum
       number of plock operations a single node will process every second.   To  achieve  maximum
       posix  locking  performance, the rate limiting should be disabled by setting it to 0.  The
       default value is 100.

         <gfs_controld plock_rate_limit="100"/>

       To optimize performance for repeated locking of the same locks by processes  on  a  single
       node,  plock_ownership  can  be  set  to  1.   The  default  is  0.   If  this is enabled,
       gfs_controld cannot interoperate with older versions that did not support this option.

         <gfs_controld plock_ownership="1"/>

       Three options can be used to tune the behavior of the plock_ownership  optimization.   All
       three  relate  to  the  caching  of  lock  ownership state.  Specifically, they define how
       aggressively cached ownership state is dropped.   More  caching  of  ownership  state  can
       result in better performance, at the expense of more memory usage.

       drop_resources_time  is the frequency of drop attempts in milliseconds.  Default 10000 (10

       drop_resources_count is the maximum number of items to drop  from  the  cache  each  time.
       Default 10.

       drop_resources_age is the time in milliseconds a cached item should be unused before being
       considered for dropping.  Default 10000 (10 sec).

         <gfs_controld drop_resources_time="10000" drop_resources_count="10"


       -D     Run the daemon in the foreground and print debug statements to stdout.

       -P     Enable posix lock debugging messages.

       -w     Disable the "withdraw" feature.

       -p     Disable posix lock handling.

       -l <num>
              Limit the rate at which posix lock messages are sent to <num> messages per  second.
              0 disables the limit and results in the maximum performance of posix locks. Default

       -o <num>
              Enable (1) or disable (0) plock ownership optimization. Default 0.  All nodes  must
              run with the same value.

       -t <ms>
              Ownership cache tuning, drop resources time (milliseconds). Default 10000.

       -c <ms>
              Ownership cache tuning, drop resources count. Default 10.

       -a <ms>
              Ownership cache tuning, drop resources age (milliseconds). Default 10000.

       -h     Print out a help message describing available options, then exit.

       -V     Print the version information and exit.


       The  gfs_controld daemon keeps a circular buffer of debug messages that can be dumped with
       the 'group_tool dump gfs' command.

       The state of all gfs posix locks can also be dumped from gfs_controld with the 'group_tool
       dump plocks <fsname>' command.


       groupd(8), group_tool(8)