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  man pages->Tru64 Unix man pages -> ypfiles (4)              



NAME    [Toc]    [Back]

       ypfiles  -  Network Information Service (NIS) database and
       directory structure

DESCRIPTION    [Toc]    [Back]

       The  NIS  database  lookup  service  uses  a  database  of
       dbm/ndbm,  btree,  or  hash files in the /var/yp directory
       hierarchy.  A dbm/ndbm database consists of two files created
  by  calls  to  the dbminit(3) function.  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 btree or hash
       database consists of a single file created by calls to the
       dbopen(3)  function.  A btree file has the filename extension
 .btree; a hash file has the extension .hash.

       A dbm/ndbm database served by NIS is called an NIS map.  A
       NIS domain is a named set of NIS maps.  Each NIS domain is
       implemented as a subdirectory of  /var/yp  containing  the
       maps.   The number of NIS domains that can exist is unlimited.
  Each domain can contain any number of maps.

       The NIS maps are not required by the NIS  lookup  service,
       although  they may be required for the normal operation of
       other parts of the system.  The NIS lookup service  serves
       all maps. If the map exists in a given domain and a client
       asks about it, NIS will serve it.  There  is,  however,  a
       set  of  default  maps  that  the NIS service serves.  The
       files representing these maps are listed in this  description
 under Files.

       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 execute
 the ypxfr command periodically should be made in  the
       /var/spool/cron/crontab/root  file  on  each slave server.
       More information on this topic is in ypxfr(8).   An  entry
       in  the  /var/spool/cron/crontab/root file must not exist,
       either on a NIS master server or  on  a  pure  NIS  client

       The  NIS  maps  should contain two distinguished key-value
       pairs.  The first is the key YP_LAST_MODIFIED, whose value
       is  a  10-character  ASCII order number.  The order number
       should be the UNIX time in seconds when the map was built.
       The second key is YP_MASTER_NAME, with the name of the NIS
       master server as a value.  The makedbm(8)  command  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.
       In  addition,  the  values  of  these two keys are used by
       ypxfr(8) when it transfers a map from a master NIS  server
       to a slave.

       Before they can be properly accessed, the NIS maps must be
       initially set up for both masters and slaves by using  the
       ypsetup(8)  function.  Further, NIS maps must be generated
       and modified only at the master server  location.   Copies
       of  the  master server NIS maps can then be transferred to
       the slave servers using the ypxfr(8) function.   If  ypxfr
       is  unable  to  determine  a  map's  location, or if it is
       unable to determine whether the local copy is more  recent
       than  the master copy, extra command line switches must be
       set when it is executed.

       After the server databases are set  up,  the  contents  of
       some  maps may change.  In general, some ASCII source version
 of the database exists on the master.   This  version
       should be changed with a standard text editor.  The update
       is incorporated into the NIS map and  is  propagated  from
       the  master to the slaves by running /var/yp/Makefile. All
       maps must have entries in /var/yp/Makefile. If an NIS  map
       is  added,  the /var/yp/Makefile must be edited to support
       the new map.  The makefile uses makedbm(8) to generate the
       NIS  map  on  the  master,  and yppush(8) to propagate the
       changed map to the slaves.  The  yppush(8)  command  is  a
       client  of  the  map ypservers, which lists all of the NIS

FILES    [Toc]    [Back]



       Commands: makedbm(8),  rpcinfo(8),  ypmake(8),  yppoll(8),
       yppush(8), ypserv(8), ypsetup(8), ypxfr(8).

       Functions: btree(3), dbm(3), hash(3), ndbm(3).  delim off

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