dlm.conf

DLM.CONF(5)                           dlm                          DLM.CONF(5)



NAME
       dlm.conf - dlm_controld configuration file


SYNOPSIS
       /etc/dlm/dlm.conf


DESCRIPTION
       The configuration options in dlm.conf mirror the dlm_controld command
       line options.  The config file additionally allows advanced fencing and
       lockspace configuration that are not supported on the command line.


Command line equivalents
       If an option is specified on the command line and in the config file,
       the command line setting overrides the config file setting.  See
       dlm_controld(8) for descriptions and dlm_controld -h for defaults.

       Format:

       key=val

       Example:

       log_debug=1
       post_join_delay=10
       protocol=tcp

       Options:

       daemon_debug
       log_debug
       protocol
       debug_logfile
       enable_plock
       plock_debug
       plock_rate_limit
       plock_ownership
       drop_resources_time
       drop_resources_count
       drop_resources_age
       post_join_delay
       enable_fencing
       enable_concurrent_fencing
       enable_startup_fencing
       enable_quorum_fencing
       enable_quorum_lockspace


Fencing
       A fence device definition begins with a device line, followed by a
       number of connect lines, one for each node connected to the device.

       A blank line separates device definitions.

       Devices are used in the order they are listed.

       The device key word is followed by a unique dev_name, the agent program
       to be used, and args, which are agent arguments specific to the device.

       The connect key word is followed by the dev_name of the device section,
       the node ID of the connected node in the format node=nodeid and args,
       which are agent arguments specific to the node for the given device.

       The format of args is key=val on both device and connect lines, each
       pair separated by a space, e.g. key1=val1 key2=val2 key3=val3.

       Format:

       device  dev_name agent [args]
       connect dev_name node=nodeid [args]
       connect dev_name node=nodeid [args]
       connect dev_name node=nodeid [args]

       Example:

       device  foo fence_foo ipaddr=1.1.1.1 login=x password=y
       connect foo node=1 port=1
       connect foo node=2 port=2
       connect foo node=3 port=3

       device  bar fence_bar ipaddr=2.2.2.2 login=x password=y
       connect bar node=1 port=1
       connect bar node=2 port=2
       connect bar node=3 port=3


   Parallel devices
       Some devices, like dual power or dual path, must all be turned off in
       parallel for fencing to succeed.  To define multiple devices as being
       parallel to each other, use the same base dev_name with different
       suffixes and a colon separator between base name and suffix.

       Format:

       device  dev_name:1 agent [args]
       connect dev_name:1 node=nodeid [args]
       connect dev_name:1 node=nodeid [args]
       connect dev_name:1 node=nodeid [args]

       device  dev_name:2 agent [args]
       connect dev_name:2 node=nodeid [args]
       connect dev_name:2 node=nodeid [args]
       connect dev_name:2 node=nodeid [args]

       Example:

       device  foo:1 fence_foo ipaddr=1.1.1.1 login=x password=y
       connect foo:1 node=1 port=1
       connect foo:2 node=2 port=2
       connect foo:3 node=3 port=3

       device  foo:2 fence_foo ipaddr=5.5.5.5 login=x password=y
       connect foo:2 node=1 port=1
       connect foo:2 node=2 port=2
       connect foo:2 node=3 port=3


   Unfencing
       A node may sometimes need to "unfence" itself when starting.  The
       unfencing command reverses the effect of a previous fencing operation
       against it.  An example would be fencing that disables a port on a SAN
       switch.  A node could use unfencing to re-enable its switch port when
       starting up after rebooting.  (Care must be taken to ensure it's safe
       for a node to unfence itself.  A node often needs to be cleanly
       rebooted before unfencing itself.)

       To specify that a node should unfence itself for a given device, the
       unfence line is added after the connect lines.

       Format:

       device  dev_name agent [args]
       connect dev_name node=nodeid [args]
       connect dev_name node=nodeid [args]
       connect dev_name node=nodeid [args]
       unfence dev_name

       Example:

       device  foo fence_foo ipaddr=1.1.1.1 login=x password=y
       connect foo node=1 port=1
       connect foo node=2 port=2
       connect foo node=3 port=3
       unfence foo


   Simple devices
       In some cases, a single fence device is used for all nodes, and it
       requires no node-specific args.  This would typically be a "bridge"
       fence device in which an agent is passing a fence request to another
       subsystem to handle.  (Note that a "node=nodeid" arg is always
       automatically included in agent args, so a node-specific nodeid is
       always present to minimally identify the victim.)

       In such a case, a simplified, single-line fence configuration is
       possible, with format:

       fence_all agent [args]

       Example:

       fence_all dlm_stonith

       A fence_all configuration is not compatible with a fence device
       configuration (above).

       Unfencing can optionally be applied with:

       fence_all agent [args]
       unfence_all


Lockspace configuration
       A lockspace definition begins with a lockspace line, followed by a
       number of master lines.  A blank line separates lockspace definitions.

       Format:

       lockspace ls_name [ls_args]
       master    ls_name node=nodeid [node_args]
       master    ls_name node=nodeid [node_args]
       master    ls_name node=nodeid [node_args]


   Disabling resource directory
       Lockspaces usually use a resource directory to keep track of which node
       is the master of each resource.  The dlm can operate without the
       resource directory, though, by statically assigning the master of a
       resource using a hash of the resource name.  To enable, set the per-
       lockspace nodir option to 1.

       Example:

       lockspace foo nodir=1


   Lock-server configuration
       The nodir setting can be combined with node weights to create a
       configuration where select node(s) are the master of all
       resources/locks.  These master nodes can be viewed as "lock servers"
       for the other nodes.

       Example of nodeid 1 as master of all resources:

       lockspace foo nodir=1
       master    foo node=1

       Example of nodeid's 1 and 2 as masters of all resources:

       lockspace foo nodir=1
       master    foo node=1
       master    foo node=2

       Lock management will be partitioned among the available masters.  There
       can be any number of masters defined.  The designated master nodes will
       master all resources/locks (according to the resource name hash).  When
       no masters are members of the lockspace, then the nodes revert to the
       common fully-distributed configuration.  Recovery is faster, with
       little disruption, when a non-master node joins/leaves.

       There is no special mode in the dlm for this lock server configuration,
       it's just a natural consequence of combining the "nodir" option with
       node weights.  When a lockspace has master nodes defined, the master
       has a default weight of 1 and all non-master nodes have weight of 0.
       An explicit non-zero weight can also be assigned to master nodes, e.g.

       lockspace foo nodir=1
       master    foo node=1 weight=2
       master    foo node=2 weight=1

       In which case node 1 will master 2/3 of the total resources and node 2
       will master the other 1/3.


SEE ALSO
       dlm_controld(8), dlm_tool(8)




dlm                               2012-04-09                       DLM.CONF(5)