[Box Backup] BadBackupStoreFile

Johann Glaser boxbackup@fluffy.co.uk
Thu, 06 Dec 2007 15:48:51 +0100


> Not exactly. It appears that if the diff times out, Box Backup will use 
> whatever matching blocks it has found so far, and resend the rest. I guess 
> which you prefer (uploading more data or spending more time diffing) 
> depends on your tradeoff between backup speed and bandwidth, but 20,000 
> seconds feels too long to me (I'd rather not have my client not upload 
> anything for six hours while it diffs).

You are right about not uploading anything while diffing, but if I
understood the BoxBackup protocol correctly, there should be
communication between server and client to negotiate the checksums.

OTOH when diffing stops after, e.g. 20 seconds, for large files this is
still a quite small fraction, so the file is uploaded every time, again
and again.

> > Hmm, using the backend data store of BoxBackup via a network (either S3
> > or NFS) is IMHO a bad idea. It would be better to have the BoxBackup
> > Server directly at the remote site so that only the BoxBackup protocol
> > (using diffs) is transmitted via the network.
> But it's not necessarily possible in all cases (e.g. unless you have an 
> Amazon EC2 server). And if you do, then you still pay something for each 
> request, and the only way to reduce the number of requests seems to be to 
> use larger files (multiple client files' blocks in a single file on the 
> server). Unless you can think of a better way?

If only the file count effects the cost of such a service, you are
right. If we want low bandwidth between server and its data storage, I
have no other idea as putting the server itself as close as possible to
the storage.


Johann Glaser                          <glaser@ict.tuwien.ac.at>
             Institute of Computer Technology, E384
Vienna University of Technology, Gusshausstr. 27-29, A-1040 Wien
Phone: ++43/1/58801-38444                Fax: ++43/1/58801-38499