Re: [rdiff-backup-users] rdiff-backup streaming?

[Dominic Raferd]

I used rdiff.exe briefly before moving to rdiff-backup. Certainly 
rdiff-backup does your 2-4 'under the hood' and fast. It is highly 
optimised both for speed of transfer and for storage space - but does 
require a reliable connection between source and destination. It does 
not do your 1, you can achieve this best by backing up from an LVM 
snapshot (if your source machine is Linux) or VSS (if it is Windows).

I am pretty sure that rdiff-backup does not use rdiff, instead it uses a 
python module built from the librsync library (which is also called, I 
think, by rdiff).

Dominic
http://www.timedicer.co.uk/

On 17/02/2011 17:41, Mark Price wrote:
> Question -
>
> We use rdiff (not rdiff-backup) to do our incremental file backups.
>
> We do:
>
>    1. Copy the file to a staging area (so the file won't disappear or
>       be modified while we work on it)
>    2. Hash the original file, and computes an rdiff signature (used
>       for delta differencing)
>    3. Comput an rdiff delta difference (if we have no prior version,
>       this step is skipped)
>    4. Compress & encrypt the resulting delta difference
>
> Our problem is all of these things happen in separate 
> phases, distinctly one from the other.  This means it takes a long 
> time to do its job.  What I am wondering is if rdiff-backup does all 
> of these things in one read/write file pass in a streaming manner, or 
> if it simply calls to the standard rdiff.exe (which isn't working for 
> us)?  I didn't quite see information concerning this in the docs or 
> wiki.  We have considered using xdelta (because it operates in a 
> streaming manner) but the problem with xdelta is that it stores double 
> copies of the deltas and kills storage space.  Any help on this matter 
> would be great!