bup-fsck(1)						      General Commands Manual						       bup-fsck(1)

NAME

       bup-fsck - verify or repair a bup repository

SYNOPSIS

       bup fsck [-r] [-g] [-v] [--quick] [-j jobs] [--par2-ok] [--disable-par2] [filenames...]

DESCRIPTION

       bup fsck is a tool for validating bup repositories in the same way that git fsck validates git repositories.

       It  can also generate and/or use "recovery blocks" using the par2(1) tool (if you have it installed).  This allows you to recover from dam-
       aged blocks covering up to 5% of your .pack files.

       In a normal backup system, damaged blocks are less important, because there tends to be enough data duplicated between backup sets  that  a
       single  damaged	backup	set  is non-critical.  In a deduplicating backup system like bup, however, no block is ever stored more than once,
       even if it is used in every single backup.  If that block were to be unrecoverable, all your backup sets would be damaged at  once.   Thus,
       it's important to be able to verify the integrity of your backups and recover from disk errors if they occur.

       WARNING: bup fsck's recovery features are not available unless you have the free par2(1) package installed on your bup server.

       WARNING:  bup  fsck  obviously  cannot recover from a complete disk failure.  If your backups are important, you need to carefully consider
       redundancy (such as using RAID for multi-disk redundancy, or making off-site backups for site redundancy).

OPTIONS

       -r, --repair
	      attempt to repair any damaged packs using existing recovery blocks.  (Requires par2(1).)

       -g, --generate
	      generate recovery blocks for any packs that don't already have them.  (Requires par2(1).)

       -v, --verbose
	      increase verbosity (can be used more than once).

       --quick
	      don't run a full git verify-pack on each pack file; instead just check the final checksum.  This can  cause  a  significant  speedup
	      with  no	obvious  decrease  in reliability.  However, you may want to avoid this option if you're paranoid.  Has no effect on packs
	      that already have recovery information.

       -j, --jobs=numjobs
	      maximum number of pack verifications to run at a time.  The optimal value for this option depends how fast your CPU can verify packs
	      vs.   your  disk throughput.  If you run too many jobs at once, your disk will get saturated by seeking back and forth between files
	      and performance will actually decrease, even if numjobs is less than the number of CPU cores on your  system.   You  can	experiment
	      with this option to find the optimal value.

       --par2-ok
	      immediately return 0 if par2(1) is installed and working, or 1 otherwise.  Do not actually check anything.

       --disable-par2
	      pretend that par2(1) is not installed, and ignore all recovery blocks.

EXAMPLE

	      # generate recovery blocks for all packs that don't
	      # have them
	      bup fsck -g

	      # generate recovery blocks for a particular pack
	      bup fsck -g ~/.bup/objects/pack/153a1420cb1c8*.pack

	      # check all packs for correctness (can be very slow!)
	      bup fsck

	      # check all packs for correctness and recover any
	      # damaged ones
	      bup fsck -r

	      # check a particular pack for correctness and recover
	      # it if damaged
	      bup fsck -r ~/.bup/objects/pack/153a1420cb1c8*.pack

	      # check if recovery blocks are available on this system
	      if bup fsck --par2-ok; then
		  echo "par2 is ok"
	      fi

SEE ALSO

       bup-damage(1), fsck(1), git-fsck(1)

BUP

       Part of the bup(1) suite.

AUTHORS

       Avery Pennarun <apenwarr@gmail.com>.

Bup unknown-															       bup-fsck(1)