Service Time. What are the "normal operation values" ?

[nicoroy123]

Hi, we have a F200 filled with 48 NL drives that are working pretty hard. IOPS still seem within an acceptable range, but the Services Time seem high to me, sometime going over 100ms. Now what I am wondering is how can I define a "service time" in the 3PAR. Are they the same as the response time of a single HDD? In that case, a service time over a 100ms would mean something very problematic. But in our scenario, beside few exeptions, most of our systems seem to perform ok, assuming they are running on NL drives.

So I am trying to define exacly what they mean by "service time"

Any thoughts welcome

[Richard Siemers]

Lets compare some numbers, how this service time is calculated has been something I have been meaning to look into. Are we looking at service time of LUNs or physical disks?

[dlorentsen]

I'll jump right in with some numbers.

P1000, V400

Normal workhours.
"3PAR V400 ServiceTime ms"
Physical Disks ServiceTime:
Read = 9-14 ms
Write = 12-19

[hdtvguy]

Service times to me is a vague area. I will tell you we have 128 NL drives in out P10000 V400 and service times are poor when they get hit hard with a few thousand IOPS. We have decided to move away form NL for everything except snapshots and some low IO CIFS servers. We are building out our 900Gb 10K tier to fill in for the NL. I can tell you that even with loads of a few hundred IOPS I can see service times get over 50ms. Our 15K and 10K tiers are well under 10 most of the time.