Not sure if much has changed, but the last time I tried to install Ceph it wouldn't work under CentOS. That, and it was far too complicated to set up.<p>GlusterFS, on the other hand, was incredibly easy, although I am not a fan of FUSE due to the high CPU usage.
FLOSS Weekly recently interviewed the Ceph project. Link to the show: <a href="http://twit.tv/show/floss-weekly/250" rel="nofollow">http://twit.tv/show/floss-weekly/250</a>
Here is a summary of how Ceph works.
<a href="http://muratbuffalo.blogspot.com/2011/03/ceph-scalable-high-performance.html" rel="nofollow">http://muratbuffalo.blogspot.com/2011/03/ceph-scalable-high-...</a>