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4203
Response Time v. Service Time
Hi. I am VERY new to storage. I was asked to collect some metrics off our CLARiiON cx4-480. I was shown how to go under the Monitoring menu to Analyze and retrieve and few archives. When viewing, I see there is both a Response Time and a Service Time, both in milliseconds. What's the difference? They both trend together in Performance Detail screen, as I assumed they would, but small spikes in Service Time can result large spikes in Response Time.
I couldn't find metric definitions for these. Can anyone help out here? Thanks!
Jyothi_P_Bharat
317 Posts
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April 2nd, 2014 09:00
Hi,
Please refer to the below mentioned thread:
https://community.emc.com/message/414423
Thanks
Jyothi
rwmastel1
2 Posts
0
April 2nd, 2014 10:00
Thanks! What really makes sense to me in that thread is:
Average I/O response time is the duration from when a request is enqueued, to the moment the disk(s) execute the request. Average service time measures the average time a disk (or RAID group) can execute a single I/O.
What ties the two together is the queue depth. Average I/O Response Time = (Queue Depth+ 1) * Average Service Time