glenda.party
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VENTI-BACKUP(8)             System Manager's Manual            VENTI-BACKUP(8)



NAME
       rdarena, wrarena - copy arenas between venti servers

SYNOPSIS
       venti/rdarena [ -qv ] arenapart arenaname

       venti/wrarena [ -o fileoffset ] [ -h host ] arenafile [ clumpoffset ]

DESCRIPTION
       Rdarena extracts the named arena from the arena partition arenapart and
       writes this arena to standard output.  This command is  typically  used
       to  back  up  an arena to external media.  The -v option generates more
       verbose output on standard error; -q generates only errors on  standard
       error.

       Wrarena  writes the blocks contained in the arena arenafile (typically,
       the output of rdarena) to a Venti server.   It  is  typically  used  to
       reinitialize a Venti server from backups of the arenas.  For example,

              venti/rdarena /dev/sdC0/arenas arena.0 >external.media
              venti/wrarena -h venti2 external.media

       writes the blocks contained in arena.0 to the Venti server venti2 (typ‐
       ically not the one using /dev/sdC0/arenas).

       The -o option specifies that the arena starts at byte  fileoffset  (de‐
       fault  0)  in arenafile .  This is useful for reading directly from the
       Venti arena partition:

              venti/wrarena -h venti2 -o 335872 /dev/sdC0/arenas

       (In this example, 335872 is the offset shown in the Venti server's  in‐
       dex  list (344064) minus one block (8192).  You will need to substitute
       your own arena offsets and block size.)

       Finally, the optional offset argument specifies that the writing should
       begin  with  the  clump  starting  at offset within the arena.  Wrarena
       prints the offset it stopped  at  (because  there  were  no  more  data
       blocks).  This could be used to incrementally back up a Venti server to
       another Venti server:

              last=`{cat last}
              venti/wrarena -h venti2 -o 335872 /dev/sdC0/arenas $last >output
              awk '/^end offset/ { print $3 }' offset >last

       Of course, one would need to add wrapper code to keep  track  of  which
       arenas  have been processed.  See /sys/src/cmd/venti/words/backup.exam‐
       ple for a version that does this.

SOURCE
       /sys/src/cmd/venti/srv

SEE ALSO
       venti(6), venti(8)

BUGS
       Wrarena can't read a pipe or network connection containing an arena; it
       needs a file already containing the entire arena.



                                                               VENTI-BACKUP(8)