Duplicity performance issue with /etc/localtime

[Tomáš Varga]

Every 10 minutes my own daemon on my server executes duplicity to backup about 100 MB of data. When doing full backup, it's ok, but sometimes while doing incremental backup it takes at least 20 minutes and whole time consumes 100 % of one CPU's core.

Some info about the data:
It's a map from game named Minecraft. (Bug caused by data format?)
The game server is running while it's doing the backup. I may not stop it. (Cause - file being sometimes overwritten during backup?)

Info about backup directory:
It's 2121464904 B large (2023,186 MB) and contains 3724 files. (Too much files in one directory?)

Duplicity version (duplicity --version): duplicity 0.6.08b
Python version (python --version): Python 2.6.6
OS (cat /etc/issue): Debian GNU/Linux 6.0 \n \l

root@delorean:~/duplicity# nohup strace duplicity -v9 --no-encryption /home/gate/world file:///opt/backup >dup 2>str &
[1] 3678
Every second there were about 4500 lines written into strace's output file.

root@delorean:~/duplicity# du -sh *
1,8M dup
1,1G str
root@delorean:~/duplicity# wc -l *
     15442 dup
  16614942 str
  16630384 celkem
root@delorean:~/duplicity# grep -vEc '^stat\("/etc/localtime"' str
35628

The duplicity output file is attached and so is strace output file without stat("/etc/localtime", ...) syscalls (in .tar file).

So, is this a bug or am I to rotate backups (move old to other folder) every few days?

[edit]
I'm not sure if the attachment got uploaded because I can't find it anywhere, so I'm pasting a link: http://213.129.147.24/dupstr.tar
[/edit]