dump

[Matthew Dillon]

:
: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
    rdist.

    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
    box.

    In anycase, it takes a little script writing and you want to use the
    lockf(1) utility to prevent cron jobs from building up.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>