Gluster users - May 2010 - question about 2 servers/clients

Hello,

I am using the following setup:

2 CentOS 5.4 i386 servers who both are using Gluster 3.0.2 with the 
latest FUSE patch.
Both servers are server/client and mount /mnt/glusterfs.
I've put my Qmail maildir (/home/vpopmail) on /mnt/glusterfs and 
symlinks to keep the /home/vpopmail link intact.
Whenever I use IMAP (dovecot server - squirrelmail/thunderbird client) I 
see some high load on the server which is receiving the imap request.

I just want to check if I got the right settings on both servers running 
both server/client model:


The client: glusterfs.vol:

volume remote1
   type protocol/client
   option transport-type tcp
   option transport.socket.nodelay on
   option remote-host server1.pcintelligence.nl
   option remote-subvolume brick
end-volume

volume remote2
   type protocol/client
   option transport-type tcp
option transport.socket.nodelay on
   option remote-host server2.pcintelligence.nl
   option remote-subvolume brick
end-volume

volume replicate
   type cluster/replicate
   subvolumes remote1 remote2
end-volume

volume writebehind
   type performance/write-behind
   option window-size 4MB
   subvolumes replicate
end-volume

volume cache
   type performance/io-cache
   option cache-size 512MB
   subvolumes writebehind
end-volume


The server: glusterfsd.vol:

volume posix
   type storage/posix
   option directory /data/export
end-volume

volume locks
   type features/locks
   subvolumes posix
end-volume

volume brick
   type performance/io-threads
   option thread-count 8
   subvolumes locks
end-volume

volume server
   type protocol/server
   option transport-type tcp
   option auth.addr.brick.allow 194.145.200.1*
   option transport.socket.nodelay on
   subvolumes brick
end-volume


Should I change some settings to get a better performance?

Servers are running 2 CPU's at 3 Ghz with 1 GB memory.

Kind regards,

Michiel