On Sun, Aug 9, 2009 at 3:06 PM, Omry Yadan<[email protected]> wrote:
> Hi all,
> I wrote a little java program that combines Rsync and ZFS snapshots to backup
> remote servers.
>
> configuration is really easy, check it out at
> http://projects.firefang.net/wiki/Zync
>
> Comments are most welcomed.
I assume that the motivation for this is to have a disk-to-disk backup
of systems that don't support ZFS. One thing that may be useful is
use of the --inplace option to rsync. This way when files that only
partially change[1] are backed up, only the parts that are different
are written to the zfs file system.
1. e.g. that 1.5 GB access_log where the first line is in 2005 and it
is still being written to
>From rsync(1):
--inplace
This causes rsync not to create a new copy of the file and then
move it into place. Instead rsync will overwrite the existing
file, meaning that the rsync algorithm can't accomplish the full
amount of network reduction it might be able to otherwise (since
it does not yet try to sort data matches). One exception to
this is if you combine the option with --backup, since rsync is
smart enough to use the backup file as the basis file for the
transfer.
This option is useful for transfer of large files with block-
based changes or appended data, and also on systems that are
disk bound, not network bound.
The option implies --partial (since an interrupted transfer does
not delete the file), but conflicts with --partial-dir and
--delay-updates. Prior to rsync 2.6.4 --inplace was also incom-
patible with --compare-dest and --link-dest.
WARNING: The file's data will be in an inconsistent state during
the transfer (and possibly afterward if the transfer gets inter-
rupted), so you should not use this option to update files that
are in use. Also note that rsync will be unable to update a
file in-place that is not writable by the receiving user.
Since you already have a zfs snapshot of the previous state, there
would seem to be no need for --backup. Also, the warning is not
terribly relevant for the same reason.
--
Mike Gerdts
http://mgerdts.blogspot.com/
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