Frequently this is from too short of a sample period.
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* email:Jeremy.Page@gilbarco.com| Servers and Storage | Gilbarco Veeder-Root
( phone: 336.547.5399 | ( cell: 336.601.7274 | 6 fax: 336.547.5163
From: owner-toasters@mathworks.com
[mailto:owner-toasters@mathworks.com] On
Behalf Of Fred Grieco
Sent: Monday, January 31, 2011
8:44 AM
To: toasters@mathworks.com
Subject: latency measurement in
DFM/Management Console/etc
How does the
Netapp or DFM measure volume and lun latency? Does it just measure how
long it's taking to service requests from the back ports to the front
ports? Or does it measure some sort of fibre ping to the host?
I am looking in the management console in DFM/Ops Mgr and seeing spikes of very
high volume and lun latency (seconds...) on an N-Series IBM gateway
filer. I've looked at all the usual suspects, including misaligned VMs,
high correlated IOPs, delays on the backend disk, deferred consistency
points. Nothing is matching up. Most of the connected systems are
on a Cisco UCS with NPIV. The systems with the lowest IOs have the
highest latency numbers.
Thoughts?
TIA,
Fred
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