Re: [BackupPC-users] Incremental Backups

[Craig B. <cba...@us...>]

"Christian G. Warden" writes:

> > Currently all incrementals are level 1, meaning they depend only
> > on the last full.  Since 2.0.0, BackupPC internals support
> > multi-level incrementals (where later incrementals depend upon
> > other incrementals), but BackupPC_dump doesn"t yet turn them on.
> > 
> [...]
> > 
> > In any case, as Les suggested, running smb over a slow high-latency
> > link will be very slow.  I recommend you try rsync.  It still only
> > does level-1 incrementals, but rsync will be a lot faster and allow
> > you to do full backups more often.
> 
> When using rsync over a slow link, does it make sense to do full backups every
> day since deltas will be against the previous day's backup?

For rsync, an incremental only processes files whose attributes have
changed.  A full processes all files.  Processing a file involves
sending block checksums to the client, and the client matches those
with the file and sends back the deltas.  So an incremental will
always be faster and use less network traffic than a full.

That said, yes, a full does provide a new baseline for the following
incrementals, so if many files have changed a full will make the
following incrementals go faster.  So it usually makes sense doing
a few incrementals between each full.  If you have large numbers of
files that change you should do fulls more often.

Craig