DLM_CONTROLD(8)

NAME
dlm_controld - daemon that configures dlm according to cluster events

SYNOPSIS
dlm_controld [OPTIONS]

DESCRIPTION
The dlm lives in the kernel, and the cluster infrastructure (corosync membership and group management) lives in user space. The dlm in the kernel needs to adjust/recover for certain cluster events. It's the job of dlm_controld to receive these events and reconfigure the kernel dlm as needed. dlm_controld controls and configures the dlm through sysfs and configfs files that are considered dlm-internal interfaces. The cman init script usually starts the dlm_controld daemon.

OPTIONS
Command line options override a corresponding setting in cluster.conf.

-D  Enable debugging to stderr and don't fork.
    See also dlm_tool dump in dlm_tool(8).

-L  Enable debugging to log file.
    See also logging in cluster.conf(5).

-K  Enable kernel dlm debugging messages.
    See also log_debug below.

-r num
    dlm kernel lowcomms protocol, 0 tcp, 1 sctp, 2 detect. 2 selects tcp if corosync rrp_mode is "none", otherwise sctp.
    Default 2.

-g num
    groupd compatibility mode, 0 off, 1 on.
    Default 0.

-f num
    Enable (1) or disable (0) fencing recovery dependency.
    Default 1.

-q num
    Enable (1) or disable (0) quorum recovery dependency.
    Default 0.

-d num
    Enable (1) or disable (0) deadlock detection code.
    Default 0.

-p num
    Enable (1) or disable (0) plock code for cluster fs.
    Default 1.

-l num
    Limit the rate of plock operations, 0 for no limit.
    Default 0.

-o num
    Enable (1) or disable (0) plock ownership.
    Default 1.

-t ms
    Plock ownership drop resources time (milliseconds).
    Default 10000.

-c num
    Plock ownership drop resources count.
    Default 10.

-a ms
    Plock ownership drop resources age (milliseconds).
    Default 10000.

-P  Enable plock debugging messages (can produce excessive output).

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

-V  Print program version information, then exit.

FILES
cluster.conf(5) is usually located at /etc/cluster/cluster.conf. It is not read directly. Other cluster components load the contents into memory, and the values are accessed through the libccs library. Configuration options for dlm (kernel) and dlm_controld are added to the <dlm /> section of cluster.conf, within the top level <cluster> section.

  Kernel options

protocol
    The network protocol can be set to tcp, sctp or detect which selects tcp or sctp based on the corosync rrp_mode configuration (redundant ring protocol). The rrp_mode "none" results in tcp. Default detect. <dlm protocol="detect"/>

timewarn
    After waiting timewarn centiseconds, the dlm will emit a warning via netlink. This only applies to lockspaces created with the DLM_LSFL_TIMEWARN flag, and is used for deadlock detection. Default 500 (5 seconds). <dlm timewarn="500"/>

log_debug
    DLM kernel debug messages can be enabled by setting log_debug to 1. Default 0. <dlm log_debug="0"/>

clusternode/weight
    The lock directory weight can be specified one the clusternode lines. Weights would usually be used in the lock server configurations shown below instead. <clusternode name="node01" nodeid="1" weight="1"/>

  Daemon options

enable_fencing
    See command line description. <dlm enable_fencing="1"/>

enable_quorum
    See command line description. <dlm enable_quorum="0"/>

enable_deadlk
    See command line description. <dlm enable_deadlk="0"/>

enable_plock
    See command line description. <dlm enable_plock="1"/>

plock_rate_limit
    See command line description. <dlm plock_rate_limit="0"/>

plock_ownership
    See command line description. <dlm plock_ownership="1"/>

drop_resources_time
    See command line description. <dlm drop_resources_time="10000"/>

drop_resources_count
    See command line description. <dlm drop_resources_count="10"/>

drop_resources_age
    See command line description. <dlm drop_resources_age="10000"/>

plock_debug
    Enable (1) or disable (0) plock debugging messages (can produce excessive output). Default 0. <dlm plock_debug="0"/>

  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.
<dlm>
  <lockspace name="foo" nodir="1">
</dlm>

  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.
<dlm>
  <lockspace name="foo" nodir="1">
    <master name="node01"/>
  </lockspace>
</dlm>
or,
<dlm>
  <lockspace name="foo" nodir="1">
    <master name="node01"/>
    <master name="node02"/>
  </lockspace>
</dlm>
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.
<dlm>
  <lockspace name="foo" nodir="1">
    <master name="node01" weight="2"/>
    <master name="node02" weight="1"/>
  </lockspace>
</dlm>
In which case node01 will master 2/3 of the total resources and node2 will master the other 1/3.

SEE ALSO
dlm_tool(8), fenced(8), cman(5), cluster.conf(5)