backup, tobackup, dumparenas, restore – backup venti arenas to blu–ray discs or restore from them

backup [ –n ] [ –d dev ] [ –s set ]
tobackup [ set ]
dumparenas dev arena ...
restore arena–# [ dev ]

These programs reside in /sys/lib/backup and provide a means to backup venti(8) storage to Blu–ray (or other large optical) discs, while keeping track of which arenas have been written to which discs. Multiple backup sets are supported, as is (re)loading a venti store from a backup thus made.

The first time that backup is run, it will dump all sealed venti arenas. Thereafter, it will append only those sealed arenas not already written to a disc within the given backup set. The –s option uses a backup set other than the default. The –d option uses a disc burner other than the default /dev/sdD0. The –n option goes through the motions but does not burn any tracks on the Blu–ray disc.

Tobackup prints the names of all the sealed arenas not yet backed up to a disc in the current set.

Dumparenas copies the named arenas, one per track, to the device dev, which is first mounted via cdfs(4). Venti/rdarena is used to extract each arena.

Tobackup and dumparenas are invoked internally by backup.

Restore copies each data track (assumed to be a saved arena) on dev (by default, /dev/sdC0) into its appropriate place in the venti arenas partition (locally, /dev/sde0/arenas), thus adding the arena to the current venti store. The arena size of the arena partition must match the size of the arenas on optical disc (except for ~60K of trailing debris on the optical disc arenas).

Arena–# must be the number (starting from zero) of the first arena slot in the arenas partition that you wish to restore into from the current optical disc (not necessarily that of the first arena on the disc). Restore will prompt for confirmation that the first arena is the correct one, after printing a summary of its arena header. Typing y will proceed normally, n will abort all processing, and skip will cause restore to proceed to the next track and ask for confirmation of it.

The arenas partition must be formatted (see fmtarenas in venti–fmt(8)) before restoring into it. When all the arenas have been restored, it will be necessary to build a new venti index, the usual steps being to run checkarenas, fmtisect, fmtbloom, fmtindex, and buildindex –b, all from venti–fmt(8).

/sys/lib/backup   backup scripts and records
set1             subdirectory containing records for default backup set
/sys/log          source of dump scores


venti(1), cdfs(4), venti(8), venti–fmt(8), venti–backup(8)
Venti Backup on Blu–Ray Discs

Assumes a single arenas partition named arena0. Assumes that the file server's arenas are accessible on it as /dev/fs/arena0.