[Samba] nfs vs. cifs based on my usage profile

[Terry]

Hello,

I have an interesting architecture consisting of a 3 RHEL 5.3 NFS
nodes that mounts about 30 TB worth of iscsi disk and presents them as
6 different NFS shares.  It is an active-active-active cluster with
each node presenting a couple of shares.  It works pretty well.  I am
doubting my decision to use NFS and am wondering if CIFS would be a
better route.  Here are the NFS stats:

getattr	lookup	access	read	write	readdirplus
20%         16%	        7%	        44%	9%	1%

Each NFS node pushes about 65 MB/s so they are pretty busy.  It is a
backup/recovery application so I would describe the I/O as lots of
small reads/writes.

Any thoughts?

Thanks,
Terry