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vrdb(5)								       vrdb(5)


NAME

       vrdb - Volume Replication Data Base specification


DESCRIPTION

       The   volume  replication  data	base  is  stored  in  binary  form  in
       /vice/db/VRDB on	each file server.  The makevrdb	option	of  the	 volu-
       til(8) program constructs the VRDB on the system	control	machine	(SCM).

       The data	base consists of fixed-length records, each of which describes
       a replicated (aka group)	volume.	 Each file server copies the VRDB into
       memory  at  start-up and	whenever an updated version of it is received.
       The data	base is	used to	map group volume names and numbers into	a  VSG
       and the set of read-write volumes which comprise	it.

       The  VRDB  is  generated	 from  an  ASCII  version stored on the	SCM in
       /vice/vol/VRList.  The VRList is	updated	as a side-effect of every cre-
       ate and purge of	a replicated volume.  Its format is:

       <group volname>	<group	volnum>	  <#  of  replicas>   <rwvol  1>   ...
       <rwvol 8>  <VSG num>

       A sample	line from the VRList is:

       project.coda.src	 7f000010  3  c9000012	ca000013  cb000013  0  0 0 0 0
       E0000107

       Note that all volume and	VSG numbers are	given in hex.  Details of  the
       VRDB structure can be found in <vrdb.h>.


FILES

       /vice/db/VRDB

       /vice/vol/VRList


BUGS

       File  servers  keep  the	 in-memory  copy  as a singly-linked list.  It
       should be converted to a	pair of	hash-tables, one keyed by  group  vol-
       name, the other by group	volnum,	for fast lookup.

       The  maximum number of replication sites	is fixed at 8.	Adding,	delet-
       ing, or moving replication sites	after creation is not supported.


SEE ALSO

       volutil (8), maxgroupid (5), vsgdb (5)


AUTHOR

       Jay Kistler, 1990, created

								       vrdb(5)

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