DragonFly users List (threaded) for 2009-06
:I installed release 2.2.2 and took the default HAMMER filesystem. When I
:tried to do a backup using dump it gave me an error complaining about a
:bad superblock. I reinstalled with the UFS filesystem. Is there a
:problem using HAMMER and dump?
dump is UFS-specific. You don't backup HAMMER filesystems using dump.
There are several ways to backup a HAMMER filesystem. Many ways, in
fact. By default HAMMER makes daily snapshots and keeps 60 days worth
around in "<fs>/snapshots/snap*/.". Backing a HAMMER filesystem can be
done using rdist or cpdup from a snapshot or it can be done using the
mirroring directives from the hammer utility.
When using cpdup or rdist you typically just use the same destination
each time (and not use any hardlink or other tricks), then snapshot the
HAMMER fs on the destination. You also typically use a snapshot as a
source so the data doesn't change out from under the running cpdup or
When using the mirroring directives one can set up a cron job to run
a batch every so often or one can set up a streaming mirror in loop
using the mirror-stream directive in the HAMMER utility, along with
bandwidth limiting options, to maintain a near-real-time backup to
a remote HAMMER filesystem.
Backups to HAMMER filesystems on another machine or off-site can be
managed independantly. I usually do a daily to a backup box on my LAN
and a weekly off-site from the LAN backup box to the off-site backup
In anycase, it takes a little script writing and you want to use the
lockf(1) utility to prevent cron jobs from building up.
- From: Jim Chapman <firstname.lastname@example.org>