Re: [rdiff-backup-users] slow incrementals over ssh to localhost

[Jeff Strunk]

On Thursday 08 March 2007 10:38 am, Randall Nortman wrote:
> On Thu, Mar 08, 2007 at 09:59:20AM -0600, Jeff Strunk wrote:
> > I just found that it takes 3 times longer to perform an incremental
> > backup via ssh of the local machine than to perform the incremental
> > backup directly.
>
> [...]
>
> It is most likely due to the CPU overhead of encrypting and decrypting
> (and possibly compressing/uncompressing) byte of data that needs to be
> "transferred".  In fact, ssh to localhost can be slower than ssh to
> another on the local network, because the CPU load is split between
> the two machines.  Given that rdiff-backup is a bit of a CPU hog on
> its own, adding the compress/encrypt/decrypt/uncompress overhead is
> likely to peg your CPU usage at 100%.  Check this while you're running
> the backup to confirm.  You are either CPU-bound or I/O-bound, and I
> suspect it's CPU.

CPU bound would be it. Thanks.