AW: [rdiff-backup-users] Severe performance degradation

[D. Kriesel]

Hi maarten,

Some questions to help myself (and the list) helping:

1) Which file systems on source and target did you use before and after the 
server change? Which other ones did you try?
2) What kind of data do you have? Millions of dirs with millions of small files 
or millions of files in just a few dirs or several very large files (gigabytes) 
or all of them?

> Still, what is observable is that any initial backup run (with --force)
> runs significantly faster on the new server.

Think so, too.

>  Any differential run
> afterwards is slower than on the original server. I feel this proves
> there are no performance bottlenecks in the network, disks, filesystems
> etc of the server.


> The new server runs rdiff-backup 1.2.8, the old one 1.0.5.

Did you upgrade the remote server too?

>  Downgrading
> the new server to 1.0.5 makes things a bit interesting: that speeds it
> up a bit, but still a fair bit slower than the original.

As of Rdiff-backup 1.1.1, hashing is done with sha-1, maybe this slows down a 
bit. Source: http://rdiff-backup.nongnu.org/CHANGELOG-stable
 
> During investigation we experimented with different filesystems, testing
> local versus remote backups, looking at compile flags and versions of
> librsync and python, but we have had no success there.

Did you try reiserfs (nice with lots and lots of small files)?