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 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
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).
- -r, --repair
- attempt to repair any damaged packs using existing recovery blocks.
- -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
- -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 recovery
bup-damage(1), fsck(1), git-fsck(1)
Part of the bup(1) suite.
Avery Pennarun <email@example.com>.
# 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"