[Box Backup] Box-Backup slow: 0.1 MiB/sec

[Felix E. Klee]

At Wed, 9 Aug 2006 17:23:33 +0200,
Baltasar Cevc wrote:
> Try to check whether the IO on the machine is the problem. My old
> backup server (which is a machine with about 2 GHz) had serious
> trouble with the whole bunch of tiny files bbstored writes.

Thanks for the hint.  I may indeed try that out.  However, first I'd
like to know whether it's possible to disable encryption of the
transmission channel and, if so, how.  Also, I'd like to know why the
transmission channel is encrypted: After all, the backups themselves are
encrypted.  So, additional encryption seems to be superfluous, something
for the paranoid.

> Just a hint: comparing the data takes quite some time, thus the first
> backup should give a higher troughput than later ones. At least that's
> what I've experienced...

This comparison thingy is probably one of the reasons why many modern
backup tools (rdiff-backup, etc.) are so extremely slow.  Star, for
example just records the time stamp associated with the last backup.
So, when doing an incremental dump, it simply checks which files have
been modified since the date in the time stamp and backs those up.  It
also doesn't compute deltas of files and it has the classical system of
multiple dump levels, so a set of incremental backups is larger than it
would be with the new fancy tools.  However, the extreme speed make up
for all those little disadvantages.  Just to give you an example: If not
many files have changed, an incremental dump of a file system with 7GB
of files may take just about a minute.  I don't expect backups to be
that fast with BoxBackup.  I'd very well be happy to wait a bit longer,
in exchange for all those nice advantages offered by BoxBackup, but
there are limits.  Going back to the example I just mentioned: BoxBackup
should not take much longer than 10 minutes to do an incremental dump of
a file system with 7GB of files, if not many have changed.

-- 
Felix E. Klee