nis_cachemgr Daemon

Commands Reference, Volume 4

nis_cachemgr Daemon

Purpose

Starts the NIS+ cache manager daemon.

Syntax

nis_cachemgr [ -i ] [ -n [ -v ]

Description

The nis_cachemgr daemon maintains a cache of the NIS+ directory objects. The cache contains location information necessary to contact the NIS+ servers that serve the various directories in the name space. This includes transport addresses, information neeeded to authenticate the server, and a time to live field which gives a hint on how long the directory object can be cached. The cache helps to improve the performance of the clients that are traversing the NIS+ name space. The nis_cachemgr daemon should be running on all the machines that are using NIS+. However, it is not required that the nis_cachemgr daemon be running for NIS+ requests to be serviced.

The cache maintained by this daemon is shared by all the processes that access NIS+ on that machine. The cache is maintained in a file that is memory mapped by all the processes. On start up, the nis_cachemgr daemon initializes the cache from the cold start file and preserves unexpired entries that already exist in the cache file. Thus, the cache survives machine reboots.

The nis_cachemgr daemon is normally started from a system startup script. The nis_cachemgr daemon makes NIS+ requests under the NIS+ principal name of the host on which it runs. Before running the nis_cachemgr daemon, security credentials for the host should be added to the cred.org_dir table in the host's domain using the nisaddcred command. Credentials of type DES are needed if the NIS+ service is operating at security level 2 (see the rpc.nisd command). Additionally, keylogin -r needs to be done on the machine.

Attention: If the host principal does not have the proper security credentials in the cred.org_dir table for its domain, then running this daemon without the -n insecure mode flag may significantly degrade the performance of processes issuing NIS+ requests.

Flags

-i	Forces the nis_cachemgr daemon to ignore the previous cache file and reinitialize the cache from just the cold start file. By default, the cache manager initializes itself from both the cold start file and the old cache file, thereby maintaining the entries in the cache across machine reboots.
-n	Runs the nis_cachemgr daemon in an insecure mode. By default, before adding a directory object to the shared cache on the request of another process on the machine, it checks the encrypted signature on the request to make sure that the directory object is a valid one and is sent by an authorized server. In this mode, the nis_cachemgr daemon adds the directory object to the shared cache without making this check.
-v	Sets verbose mode. In this mode, the nis_cachemgr daemon logs not only errors and warnings but also additional status messages. The additional messages are logged using syslog with a priority of LOG_INFO.

Diagnostics

The nis_cachemgr daemon logs error messages and warnings using syslog. Error messages are logged to the DAEMON facility with a priority of LOG_ERR and warning messages with a priority of LOG_WARNING. Additional status messages can be obtained using the -v flag.

Files

/var/nis/NIS_SHARED_DIRCACHE	Contains the shared cache file
/var/nis/NIS_COLD_START	Contains the coldstart file
/etc/init.d/rpc	Contains initialization scripts for NIS+

Related Information

The keylogin command, nisaddcred command, nisinit command, nisshowcache command.

The rpc.nisd daemon .