PD Service Time

[oby]

Hi,

what's you typical service time for write/read on the physical disks?

toby

[nsnidanko]

10K FC (we have AO with SSD for heavy volumes)

[oby]

okay, my write servicetimes are way to high (20ms). I think I'll change from Raid5 to Raid1 and AO is enabled.

[oby]

Hi,

okay my Ports Performance Statistics. Is it average, good or bad? Anyone a opinion?

[Cleanur]

Which ports, front end, back end or both ?

[oby]

The chart is from the front end ports.

[nsnidanko]

It does look quite busy but you need to look at your workload. For some applications anything below 20ms is acceptable while for other applications anything above 5ms will be an issue.

We were pushing our system to its max and were seeing similar response time with 10K FC drives (3par is great technology to deliver this workload without any hiccups).

If you have 3.1.3 I highly suggest you run region density reports and find out how much data is causing how much IO. We discovered we had X TBs of data responsible for 80% of our IO. So we invested into SSD+AO and our front end response time dropped to sub 3ms

In 3.1.3 you can run density reports for individual VV and see how much "hot" data you have per each volume.

If you don't have AO licenses wait for Flash cache to come out and it might do that trick for you by simply putting some SSDs (Note: Flash Cache is only for reads).

Raid 5 to Raid 1 will give you very slim performance gains as I believe 3par's Raid 5 is 80% performance of raid 1.

[oby]

Hi,

we have AO and our AO Policy is set to Performance.

[nsnidanko]

Hi,

we have AO and our AO Policy is set to Performance.

what are your tiers? Raid 5 10K to Raid 1 10K?

[oby]

My tiers are SSD R5 3+1 -> FC 15k R5 3+1 -> NL 7K R6 6+2. Perhaps the high service time comes from the NL disks.