CIFS read-ahead

[Nicholas M. Kirsch]

I have two W2k3 machines, on GigE, one with a 2GB ramdisk acting as a
server, one as a client. Try as I might, I cannot achieve more than about
250 MBs in a single-stream sequential read -- which I imagine can be
blamed on latency. I have heard rumours of the ability to enable
read-ahead for CIFS clients -- is this possible, or just a rumour? And if
possible, can anyone offer some tips?

Of course, I have tried an identical configuration with FreeBSD and Samba
3.0 acting as the server, with the same speed as the result. Both machines
are quite powerful, and I can achieve almost twice the throughput with
NFS. I was told that NFS does aggressive read-ahead, and this was
responsible for the difference.

If Samba cannot currently support read-ahead, but CIFS clients can be made
to do so, I am interested in adding said support to Samba.

Thank you.

Nicholas Kirsch <nkirsch at isilon.com>
Applications Developer, Isilon Systems Inc.

http://www.isilon.com/