NAME

       gfmdhost - Gfarm metadata server host maintenance command

SYNOPSIS

       gfmdhost [-l] [-P path] [-1]

       gfmdhost [-N] [-P path] [-1]

       gfmdhost {-c | -m} [-P path] [-1] [-p port-number] [-C cluster-name] [-t {m | c | s}]
                {metadata-server-name}

       gfmdhost {-d} [-P path] [-1] {metadata-server-name}

DESCRIPTION

       gfmdhost is used to display and maintain the information about synchronous and
       asynchronous replicated metadata servers.  gfmdhost has functions which can be selected by
       -l, -c, -m and -d options. These functions are mutually exclusive, and only one option
       among them can be specified. If none of them is specified, registered metadata server
       (gfmd host) names will be listed.

FUNCTIONS

       The functions of gfmdhost command are listed in following.

       <none>
           If no function is specified, all the registered gfmd hosts are displayed in
           alphabetical order.

       -l
           All registered gfmd hosts are listed with detailed information. They are grouped by
           the clusters and ordered alphabetically.

           The detailed information is displayed in the following order.

           Connection State (+|||-|?|x|e|u)

           "+" means that the gfmd is connected to the master gfmd, and its metadata are
           synchronized. "|" means that the gfmd is connected to the master gfmd, but its
           metadata have not been synchronized yet. Note that this may happen even on a
           synchronous slave gfmd, when the slave is just connecting to the master, or in the
           middle of metadata transfer even if it has been already synchronized. "-" means that
           the gfmd is not connected to the master gfmd. "?" means either the gfmd state is
           unknown because it's just after the connection was established, or the master gfmd is
           Gfarm-2.5.0, but this gfmdhost command is 2.5.1 or later. "x" means that the
           connection with master gfmd was established, but automatic synchronization was
           impossible because of too many metadata changes, thus, manual synchronization via dump
           and restore of the backend database is necessary. "e" means an error happened, and log
           file must be checked manually. In the case of "x" or "e", it may be displayed even
           when the slave gfmd is down. "u" means that the slave gfmd is connected to the master
           gfmd, but the state is not supported by this gfmdhost command. This column for the
           master gfmd is always "+".

           Server Type (master|slave)

           This represents whether the gfmd is master or slave.

           Replication Type (sync|async|-)

           "sync" means a synchronous replication. "async" means an asynchronous replication.
           This column for the master is always "-".

           Configration of Master Candidate (c|m|s)

           "m" means the default master gfmd, "c" means a master candidate that can be selected
           as a master gfmd, and "s" means a gfmd that is not a master candidate and only works
           for a slave gfmd.

           Cluster Name

           A cluster name where the gfmd belongs to. "(default)" is displayed for the default
           cluster.

       -N
           Displays a hostname and port number of the connected metadata server.

       -c
           Registers the gfmd host that is specified in the argument. -C, -p, -t can be
           optionally specified.

       -m
           Modifies the gfmd host that is specified in the argument. -C, -p, -t can be optionally
           specified.

       -d
           Deletes the gfmd host that is specified in the argument. The master gfmd cannot be
           deleted.

       -?
           Prints usage.

OPTIONS

       -C cluster-name
           This option specifies a cluster name where the gfmd host belongs to. If it is not
           specified, the default cluster is assumed. This option is only available with -c or -m
           option.

           The cluster name means a group of synchronous replicated metadata servers. That is,
           slave metadata servers in the same cluster with the master metadata server are
           synchronously replicated servers that can be changed to a master metadata server
           without any loss of metadata operations. Other metadata servers are asynchronously
           replicated servers.

       -p port-number
           This option specifies a port number of the gfmd. If it is not specified, 601 is
           assumed. This option is only available with -c or -m option.

       -t {m|c|s}
           This option specifies a configuration of master candidate. It is only available with
           -c or -m option. "m" means the default master, "c" means a master candidate and and
           "s" means a slave only gfmd. If it is not specified, "c" is assumed. The gfmd
           configured as the default master cannot be changed to a master candidate or slave-only
           directly. If the gfmd that is not the default master is changed to the default master
           by "-t m", the original default master is changed to a master candidate at the same
           time.

       -P path
           This option specifies a pathname or a Gfarm URL to identify a metadata server which
           will be accessed by this command. If not specified, "/" is used as the default value.

       -1
           With this option, gfmdhost only tries to connect with one metadata server specified by
           -P option, or if missing, metadb_server_host statement in gfarm2.conf file.

SEE ALSO

       gfarm2.conf(5)