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 perlockspace nodir option to 1.
- <dlm>
<lockspace name="foo" nodir="1"> - </dlm>
- Lock-server configurationThe 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.