ypfiles(4) — Reliant UNIX 5.44c4

ypfiles(4)                                                       ypfiles(4)

NAME
     ypfiles - the NIS database and directory structure

DESCRIPTION
     NIS uses a distributed, replicated database of dbm files contained in
     the /var/yp directory hierarchy on each YP server. A dbm database con-
     sists of two files, one has the filename extension .pag and the other
     has the filename extension .dir. For instance, the database named
     hosts.byname is implemented by the pair of files hosts.byname.pag and
     hosts.byname.dir.

     A dbm database for a given source file (e.g. /etc/inet/hosts) is
     called a NIS map. A NIS "domain" is a subdirectory of /var/yp contain-
     ing a set of NIS maps. Any number of NIS domains can exist. Each may
     contain any number of maps.

     For a map to be accessible consistently, it must exist on all NIS
     servers that serve the domain. To provide data consistency between the
     replicated maps, an entry to run ypxfr periodically should be made in
     the privileged user's crontab file on each server. More information on
     this topic is in ypxfr(1M).

     NIS maps should contain two distinct key-value pairs. The first is the
     key YPLASTMODIFIED, having as a value a ten-character ASCII stamp.
     The stamp should be the system time (in seconds) when the map was last
     updated. The second key is YPMASTERNAME, with the name of the YP
     network administration host as a value. makedbm(1M) generates both
     key-value pairs automatically. A map that does not contain both key-
     value pairs can be served by the NIS, but the ypserv process will not
     be able to return values for "Get order number" or "Get master name"
     requests. See ypserv(1M). In addition, values of these two keys are
     used by ypxfr when it transfers a map from a network administration
     host to a server. If ypxfr cannot figure out where to get the map, or
     if it is unable to determine whether the local copy is more recent
     than the copy on the network administration host, then options must be
     set when it is run.

     NIS maps are to be generated and modified only at the network adminis-
     tration host. After the server databases have been set up, it is prob-
     able that the contents of some maps will change. In general, some
     ASCII source version of the database exists on the master, and it is
     changed with a standard text editor. The update is incorporated into
     the YP map and is distributed to the other servers by running
     /var/yp/Makefile; see ypmake(1M). A range of standard maps have
     entries in /var/yp/Makefile; if an NIS map is added, edit this file to
     support the new map. The makefile uses makedbm(1M) to generate the NIS
     map on the network administration host, and yppush(1M) to distribute
     the changed map to the other servers.







Page 1                       Reliant UNIX 5.44                Printed 11/98

ypfiles(4)                                                       ypfiles(4)

FILES
     /var/yp

     /var/yp/aliases

     /var/yp/Makefile

SEE ALSO
     makedbm(1M), ypinit(1M), ypmake(1M), yppoll(1M), yppush(1M),
     ypserv(1M), ypxfr(1M), dbm(3C).












































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