Help -- rsync Causing High Load Averages

[Plugger]

This is my situation and I am running into dead ends.

We have a server with about 400GB of data that we are trying to backup
with rsync. On the content1 server we had rsyncd.conf as:

[content1]
   path = /
   comment = Backup
   list = no
   read only = yes
   hosts allow = 192.168.22.181
   hosts deny = *
   uid = root
   gid = root

and on the backup server we had a crontab entry as follows:

0 7 * * * /usr/bin/rsync -av --stats --delete 192.168.22.182::content1
/var1/content1

This will pull everything over to the backup server. When it runs,
however, the load averages on the content1 server continue to grow to
the 100s, bringing the server to a practical standstill. After a day of
tweaking, and killing the content1 server periodically, I have not been
able to reduce the loads much.

Both servers are dual xeon 3.0 with about 1TB of storage configured in a
RAID5 with SATA drives, and a separate OS drive. Running CentOS version
2.6.15.6. Rsync version 2.6.7  protocol version 29.

I tried tweaking the rsync commands and this is where I ended up, but
still it eventually brings the load average up and the sever to it knees.

So now, rsyncd.conf on the content1 server is:

max connections = 1

[content1]
   path = /
   comment = Backup
   list = no
   read only = yes
   hosts allow = 192.168.22.181
   hosts deny = *
   uid = root
   gid = root

I also created a shell script to start rsync in daemon mode:

#!/bin/sh
exec nice -n 19 /usr/bin/rsync --daemon $*

That was to try to get the load down.

Here is a snapshot of the load now and it is pushing 50.7 Mbits/sec:

top - 17:42:50 up 14 days, 21:53,  2 users,  load average: 0.23, 0.33, 1.06
Tasks: 467 total,   1 running, 466 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.4% us,  0.8% sy,  0.0% ni, 88.5% id, 10.2% wa,  0.1% hi,  0.0% si
Mem:   4148912k total,  4131716k used,    17196k free,    10112k buffers
Swap:  1020116k total,     1000k used,  1019116k free,  3783936k cached

On the backup server we tried:

/bin/nice -n 19 /usr/bin/rsync -rlptgoWv --stats --delete-after
192.168.22.182::content1 /var1/content1

We are not worried about network traffic, as these 2 servers are
connected via a LAN. Most of the files are images and media files.

I have not had problems with rsync in the past, and 3 other servers,
much smaller, are being backed up just fine. I am not sure what other
tweaks I can use, so any suggestions on how to keep the load averages
rising to the point where the server is useless would be appreciated.

Thanks
Ron