bup-fsck - verify or repair a bup repository
bup fsck [-r] [-g] [-v] [--quick] [-j jobs
] [--par2-ok] [--disable-par2]
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 damaged
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
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.
: bup fsck's recovery features are not available unless you have
the free par2(1) package installed on your bup server.
: 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
- -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).
- 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
- immediately return 0 if par2(1) is installed and working,
or 1 otherwise. Do not actually check anything.
- pretend that par2(1) is not installed, and ignore all
# 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!)
# 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"
bup-damage(1), fsck(1), git-fsck(1)
Part of the bup(1) suite.
Avery Pennarun <email@example.com>.