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maxgroupid(5) - maxgroupid - replicated volume number allocation mechanism - man 5 maxgroupid

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maxgroupid(5)                                                    maxgroupid(5)



NAME
       maxgroupid - replicated volume number allocation mechanism





DESCRIPTION
       The  system  control  machine  (SCM)  has a file(1,n), /vice/vol/maxgroupid,
       which contains the maximum replicated (aka group)  volume  number  that
       has ever been allocated in(1,8) the system.  This is used as a simple way to
       guarantee that group volume numbers are unique.

       Replicated (or group) volume ids  are allocated out of the same  names-
       pace  as  replica  ids  and non-replicated volumes ids.  The latter two
       types of ids have a 1 byte (8 bit) prefix to  identify  the  server  on
       which  they  are  stored.  We suggest using prefixes in(1,8) the range 00-7F
       for replicated volume ids, and prefixes in(1,8) the range  80-FF  for  other
       volumes.   When  initializing  a system, put the number you wish to use
       for the first replicated volume in(1,8) /vice/vol/maxgroupid.  For  example,
       if(3,n)  you  wish  to  use  7f000000 as the first replicated volume, create
       /vice/vol/maxgroupid with the number 2130706432.




FILES
       /vice/vol/maxgroupid on the SCM




BUGS
       This file(1,n) should be salvaged, but it is not.

       Removing this file(1,n) (without  reinitializing  the  whole  system)  is  a
       recipe  for  disaster.   Grave  confusion  will result if(3,n) group (or any
       other) volumes are created with the same number.




SEE ALSO
       servers (5), createvol_rep (8)




AUTHOR
       Jay Kistler, 1990, Created





                                                                 maxgroupid(5)

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