Cache Manager Daemon

Cache Manager Daemon

dbis-cachemgr is a multi-threaded daemon responsible for responding to client requests for information, performing LDAP search operations against LDAP directory servers and maintaining an in-memory cache of recently requested data.

It listens on two sockets, one that the NSS library uses and one that the dbis client tool and Python API make use of. These sockets are configurable.

The number of sockets and maximum number of simultaneous connections are also configurable. dbis-cachemgr is optimised for heavy loads, being able to respond quickly to client requests even on busy servers with lots of NSS lookups going on, and will share LDAP search operations between clients when the same data is being requested.

The daemon accepts a small number of command-line arguments and a larger number of configuration options in the /etc/dbis-cachemgr.conf configuration file.

Command-line arguments

dbis-cachemgr accepts the following command-line arguments:

Option	Description
-c (--cfgfile) file	Specify an alternative configuration file. This may also be modified using the DBIS_CFGFILE environment variable. The default is /etc/dbis-cachemgr.conf.
-D (--debug)	Turn on debug mode. This does not affect the debug level, which is defined in the configuration file, however it does instruct the program not to daemonize, and not to redirect stdout.
-d (--dbis-socket) socket	Specify an alternative listen socket to use for DBIS client connections, i.e. from the dbis client tool or Python API. The default is /var/run/dbis/client.
-h (--help)	Display help message.
-n (--nss-socket) socket	Specify an alternative listen socket to use for NSS library connections. The default is /var/run/dbis/nss.
-o (--output) file	Redirect stdout to the specified file when daemonizing. This option is ignored in debug mode.
-p (--pidfile) file	Specify an alternative PID file. The default is /var/run/dbis-cachemgr.pid.
-v (--version)	Display program version and copyright message, then exit.

Signals

dbis-cachemgr responds to the following signals:

Signal	Description
SIGINT, SIGTERM, SIGHUP	Stop server gracefully.
SIGUSR1	Save stack dump to /var/tmp/dbis-cachemgr.stackdump.<pid>.
SIGUSR2	Save statistics file to /var/tmp/dbis-cachemgr.stats.<pid> listing all maps in cache and how many entries they have with hit and miss counters.

For more information on the other components of DBIS, see [Using DBIS].