Hmm...what reason would you expect the line latency to be _different_ from host to host, to the same filer?
On Wed, Feb 1, 2012 at 11:30 PM, Randy Rue rrue@fhcrc.org wrote:
I appreciate your feedback.
I'm attempting to get some real-time view of current latency for NFS mounts, but have figured out that running nfsiostat returns the average since boot. Running it with multiple iterations in one call seems to return transient data, but running a single 1 second iteration doesn't.
Our ultimate goal is to capture instantaneous latency figures from several clients, post the average of those latencies and the single worst figure into an RRD database, and give a graph showing average and worst case. Can you suggest a way to do this with nfsiostat, or a better way with some other tool?
----- Original Message ----- From: "Andrey Borzenkov" andrey.borzenkov@ts.fujitsu.com To: "Randy Rue" rrue@fhcrc.org, toasters@teaparty.net Sent: Wednesday, February 1, 2012 7:33:02 PM Subject: RE: nfsiostat and client NFS connections
You do not say how you process results nor how you run nfsiostat.
nfsiostat (just like iostat, vmstat, ...) reports delta for measurement interval. The very first line is always totals since kernel boot. Usually nfsiostat is run with interval argument ("nfsiostat 60" will give you stats every minute). If you invoke it every minute you have to compute delta yourself.
There are other ways to collect information in form easier to postprocess than nfsiostat free form text output. Sadc + sadf to produce CSV, XML or other formats (which are part of the same sysstat package), collectl (can maintain RRD database) etc.
From: toasters-bounces@teaparty.net [toasters-bounces@teaparty.net] On Behalf Of Randy Rue [rrue@fhcrc.org] Sent: Thursday, February 02, 2012 02:33 To: toasters@teaparty.net Subject: nfsiostat and client NFS connections
Hello All,
Trying to troubleshoot performance problems on our v3170. This is not specifically a NetApp question but if nothing else, the tool I'm using appears to have been written by a NetApp engineer, does that count?
Running nfsiostat on a handful of impacted clients on another network and uploading the results to a timestamped log file served on a web server so I can reach them. I have a script that parses those pages, takes the last timestamped entry from each file (one file for each client), and tallies up a) the average RTT time for all mounts to the vFiler and b) the worst single instance.
Now that I have it all working, the numbers don't believe like I think they should. The clients are adding an entry to each file every minute. I can see that from the timestamps before each entry. But the numbers don't change. Or they change by a few hundredths of a ms. My gather script returns an average that varies only by .01ms or so, and my "worst" figure has been steady for an hour now.
We're running nfsiostat with no arguments. Am I getting real time readings or some average? If average, since when? Is there a way to get real-time?
Hope to hear from you,
Randy Rue
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