DC_SERVER(1)                                                distcache                                               DC_SERVER(1)



NAME
       dc_server - Distributed session cache server

SYNOPSIS
       dc_server -listen <address> [options]

DESCRIPTION
       dc_server runs a cache server and starts listening on a configurable network address for connections. Incoming connec-
       tions are expected to communicate using the distcache(8) protocol, and would typically be instances of dc_client(1) run-
       ning on other machines.

OPTIONS
       -daemon
           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.

       -user user
           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).

       -listen address
           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

       -sockowner user
           This switch is only useful when listening (see -listen) on unix domain sockets.  It will attempt to change ownership
           of the created socket file.

       -sockgroup group
           This switch is only useful when listening (see -listen) on unix domain sockets.  It will attempt to change group own-
           ership of the created socket file.

       -sockperms perms
           This switch is only useful when listening (see -listen) on unix domain sockets.  It will attempt to change file per-
           missions 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

       -sessions num
           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.

       -progress num
           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 used.

       -pidfile path
           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 path was);

               kill `cat pidfile.pid`

       -killable
           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
       dc_client(1)
           Distributed caching client proxy.

       dc_snoop(1)
           Distcache protocol analyser and debugging tool.

       distcache(8)
           Overview of the distcache architecture.

       http://www.distcache.org/
           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 geoffATgeoffthorpe.net.

       Home Page: http://www.distcache.org



1.4.5                                                      2004.03.23                                               DC_SERVER(1)