continuous backup solution for FreeBSD

[Oliver Fromme]

Dag-Erling Smørgrav wrote:
 > "Zaphod Beeblebrox" <zbeeble at gmail.com> writes:
 > > "Dag-Erling Smørgrav" <des at des.no> writes:
 > > > What really annoys me with this thread is that nobody has provided
 > > > any information at all that would allow someone to understand what
 > > > needs to be done and estimate how hard it would be.
 > > Well... I hinted that a hammer port would be sufficient (although they
 > > need to finish their replication design) and I hinted that the hammer
 > > approach may be graftable to ZFS.  Both reasonably large effort-wise
 > > (but probably within the scope of a single developer with sufficient
 > > time).
 > 
 > No...  you're so far off the mark it's not even funny, especially when
 > it's been repeatedly pointed out to you.  This is not a file system,
 > it's a backup system.  It's not designed to survive a disk crash or an
 > accidental file deletion, it's designed to survive a direct missile
 > strike on your colo center.
 > 
 > To quote Wikipedia, "CDP is a service that captures changes to data to a
 > separate storage location" - emphasis on "separate".

FWIW, the HAMMER file system _does_ support replication to
remote targets (thus "separate").  Unfortunately they call
this feature "mirroring", which is misleading at best.
It's really rather a replication mechanism, much like the
binlog of MySQL.  It can be used for various purposes,
including live mirroring, delayed mirroring, archiving,
backup and point-in-time recovery.

Well, of course, all of that doesn't help us at all because
HAMMER doesn't exist on FreeBSD.

However, ZFS does exist on FreeBSD, and I think it wouldn't
be impossible to add similar features to ZFS.

Another possibility would be to extend gjournal by adding
time stamps to journal transactions and a possibility to
feed the journal to a pipe, socket or whatever.  And of
course a client-side implementation that does something
useful with the journal stream.  This might even be a good
SoC project.

Best regards
   Oliver

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