The nis_cachemgr daemon maintains a cache of NIS+ directory objects and active servers for domains. It is responsible for locating servers for a domain on behalf of client processes.
This improves performance because only one process has to search for servers. The cache contains location information necessary to contact the NIS+ servers. 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. nis_cachemgr should be running on all the machines that are using NIS+. However, it is not required that the nis_cachemgr program
be running in order for NIS+ requests to be serviced.
The cache maintained by this program is shared by all the processes that access NIS+ on a machine. The cache is maintained in a file that is memory mapped by all the processes. See mmap(2). On start up, nis_cachemgr initializes the cache from the cold start file and preserves unexpired entries that already exist in the cache file. See nisinit(1M). Thus, the cache survives machine reboots.
The nis_cachemgr program is normally started from a system startup script. nisshowcache(1M) can be used to look at the cached objects and active servers.
The nisprefadm(1M) command can be used to control which NIS+ servers the nis_cachemgr program will try to select.
The nis_cachemgr program makes NIS+ requests under the NIS+ principal name of the host on which it runs. Before running nis_cachemgr, security credentials for the host should be added to the cred.org_dir table in the host's domain using nisaddcred(1M). Credentials of type DES will be needed if the NIS+ service is operating at security level 2 (see rpc.nisd(1M)). See the DIAGNOSTICS section, below. Additionally, a "keylogin -r " should be done on the machine.
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