On 07/28/10 03:21 PM, Sebastien Godard wrote:
On 07/28/2010 07:40 PM, Chuck Lever wrote:
On 07/28/10 05:45 AM, Or Gerlitz wrote:
Trond Myklebust wrote:
On Tue, 2010-07-27 at 13:07 +0300, Or Gerlitz wrote:
Doing some iscsi and nfs performance testing, I realized that
iostat(1)
doesn't support an "await" like counter for measuring nfs latency.
Can tracking nfs latency be done in other means? is there a plan to
extend the nfs iostats code to include such/similar counter?
The information is already available in /proc/self/mountstats. It is up
to iostat to start using it.
Sebastian, is there a plan to support await like counter in sysstat?
I didn't find a source repository (is there an open one? where?) so
downloaded the latest code (version 9.1.3) drop from the website and
couldn't see there such a counter, am I missing something?
There are Python scripts in nfs-utils that report the statistics in
/proc/self/mountstats. Nobody really likes the file format of
/proc/self/mountstats, so the plan is to move these, at some point, to
someplace where perf can report them.
At that point, iostat support would also be nice.
I'm ready to accept a patch that would add an await like counter to
measure NFS latency.
What is await, precisely?
And, by "NFS latency" do you mean read/write latency or something else?
For NFS, even stat() can require server interaction (ie is not served
from the system's local memory)
BTW beginning with sysstat version 9.1.3, there is a specific command
("nfsiostat") aimed at displaying stats for network filesystems.
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