Hi

compared to ext3 i found reiserfs is faster for me..However my environment is mostly OPLTP and batch type..it is the way to go for me.You need to experiment with the filesystem types .ext3 is supported by redhat 7.3.The 2.4 kernels have reiserfs built into them.
If you plan to use RAC then ocfs is the way to go..I have been hearin about reaierfs 4.0.If you can wait for a few months then resierfs 4.0 is the way to go..it would have better integration with 2.6 kernel and better async I/o capabilites..

regards
Hrishy