RE: re[2]: [rdiff-backup-users] ACLS

[Spicer, Kevin]

> 
> Is there any way to have the backup be compressed?
> 
> I have spent the last couple of hours looking for a Linux 
> Compressed Filesystem and I found nothing.
> 
> I'm not positive I need compression, but I'm just used to 
> compressing backups.

IIRC There are essentially two main elements to an rdiff-backup backup.
1) A mirror of your source directory at the time rdiff-backup last ran
2) a set of increments (diffs) to allow you to restore the mirrored files to a 
previous state
[I know thats over simplified and there is other data stored, such as metadata]
The increments themselves (which tend to be small anyway, unless you have a 
hugely active filesystem) are compressed by default.  The mirror itself is not 
compressed, and should not be since if it were each file would need to be 
uncompressed on the fly every time it needs to be compared to the file in the 
source directory.

To give you some idea (other may have different experiences) my destination 
directory is 110% the size of the source directory and I keep two weeks of 
increments  - I've never run out of space (note that this is only my experience 
- different levels of activity on a filesystem with result in different 
quantities of diffs).  I reckon you've got it about right if the destination 
directory and the source directory are about the same percentage full most of 
the time. 

I've found rdiff-backup to be very stable in recent versions although I'd 
always advocate taking regular tape backups, apart from anything else you can 
probably keep a tape backup for longer than you are likely to store the rdiff 
increments.  However the ability to do near instantaneous restores is where 
rdiff-backup really shines.



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