measuring NFS read/write latencies

I just posted this as a question on Kevin Closson's blog but actually it might be a good one for the list...

iptraf is a nice way to monitor NFS throughput (I just did a blog post this morning about it) - but does anyone know any way to measure latencies at the OS level for NFS? For block devices iostat reports it in the "await" and "svctm" columns (the former includes time in the request queue) - but I'm not sure how I could do this with NFS devices and it's a piece of information I'd really like to know. Oracle reports some figures for datafiles but I'd like to see figures from a lower level and I don't think Oracle measures latencies on files such as online logs, archive logs, or control files. (Or does it?)

-Jeremy

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Jeremy Schneider
Chicago, IL
http://www.ardentperf.com/category/technical

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http://www.freelists.org/webpage/oracle-l