| DLM_CONTROLD(8) | cluster | 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 0. - -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="0"/>
- 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¶
| 2009-01-18 | cluster |