Distributed session cache server. It runs a cache server and starts listening on a configurable network address for connections.
Now lets see the manual of dc_server service.Manual dc_server:NAME
dc_server - Distributed session cache serverSYNOPSIS
dc_server -listen <address> [options]DESCRIPTION
dc_server runs a cache server and starts listening on a configurable network address for connections. Incoming connections
are expected to communicate using the distcache(8) protocol, and would typically be instances of
dc_client(1) running on other machines.OPTIONS
After initialising, dc_server will detach from the parent process, close standard file-descriptors, etc. If
this flag is not set, dc_server will run in the foreground. It is recommended to use this flag in combination
with the pidfile flag to simplify stopping and restarting services.
This switch will attempt to change user privileges of dc_server to the given user ID after initialising its
listening socket. On most systems, this can only work if dc_server is started as the root user. It is important
to note that the change of user ID occurs after the listening socket is create. This ensures that the listening
socket is created with the most restrictive permissions, and that the ability to connect to servers at run-time
corresponds to the given user (rather than having unusual root permissions on startup).
Configures the address on which dc_server should listen for incoming connections. The syntax is that defined
by the libnal API. Some examples follow;
# Listen on port 9001 for all TCP/IPv4 interfaces
dc_server -listen IP:9001
# Listen on port 9001 on a specific TCP/IPv4 interface
dc_server -listen IP:192.168.0.1:9001
dc_server -listen IP:cacheserver.localnet:9001
# Listen on a unix domain socket in the /tmp directory
dc_server -listen UNIX:/tmp/cacheserver
This switch is only useful when listening (see -listen) on unix domain sockets. It will attempt to change ownership
of the created socket file.
This switch is only useful when listening (see -listen) on unix domain sockets. It will attempt to change
group ownership of the created socket file.
This switch is only useful when listening (see -listen) on unix domain sockets. It will attempt to change file
permissions for the created socket file, and is specified in the standard octal notation used for unix file
permissions. Eg. to start dc_server to run as the nobody user, listening on a unix domain socket that can only
be connected to by the root user or members of the dcclient group;
# dc_server -listen UNIX:/tmp/cacheserver -user nobody
-sockgroup dcclient -sockperms 440
Specifies a maximum number of sessions that should be stored in the cache. All sessions in a cache have an
expiry time so that they will, if they have not been forcibly removed before that time, be expired out of the
cache. If it is desirable to allow long session timeouts under normal situations yet protect against the session
cache growing without limit periods of high-load, this limit can provide the required balance. If the session
cache reaches this limit, it will automatically rotate out those sessions in the cache that are due to
expire soonest. It is not (yet) possible to have no limit at all, though a future version should support this
by allowing the user to specify zero.
The default value for this flag is 512.
dc_server will, by default, log a line of output to stdout whenever there is cache activity, but will make sure
to do so no more often than once a second. If -progress is specified, this will take precedence so that output
will be emitted whenever num operations have occurred since the last output, irrespective of how little
time has elapsed. The once-a-second logic remains behind this, so that if less than num operations has taken
place but at least one second has passed, output will still be logged. This flag has no effect if -daemon is
This is a standard flag for many programs, and most useful in combination with -daemon. When -pidfile is specified
dc_server will write its process ID to a file at the specified path upon successful initialisation. To use
this path file to later kill the running dc_server instance, use something like (where pidfile.pid is whatever
kill 'cat pidfile.pid'
The default behaviour of dc_server is to silently ignore SIGUSR1 and SIGUSR2 signals, but with this switch
enabled it will handle these signals and close down cleanly (mainly useful for developers as an alternative to
SIGKILL which is less useful for debugging memory leaks).
-h, -help, -?
Any of these flags will cause dc_server to display a brief usage summary to the console and exit cleanly. Any
other flags are ignored.SEE ALSO
Distributed caching client proxy.
Distcache protocol analyser and debugging tool.
Overview of the distcache architecture.
Distcache home page.AUTHOR
This toolkit was designed and implemented by Geoff Thorpe for Cryptographic Appliances Incorporated. Since the
project was released into open source, it has a home page and a project environment where development, mailing
lists, and releases are organised. For problems with the software or this man page please check for new releases at
the project web-site below, mail the users mailing list described there, or contact the author at
Home Page: http://www.distcache.org