PS6000e Disk Latency and Max KBps

To validate performance in your Equallogic Storage Area Network, I would recommend using SAN Headquarters to monitor performance.
Link (https://www.equallogic.com/support/download.aspx?id=9767)

Performance though, is very subjective to your environment and will depend on many factors. I would suggest using SAN HQ to monitor status and then do a run through verifying hardware and configuration best practices. You can find some great documentation on the Equallogic site to assist with best practices..
link (https://www.equallogic.com/support/resources.aspx)

"Hi

We have a Dell Equallogic PS4000e and a 6000e all with SATA disks.

The disks are setup as RAID 10

We are running SAP on a virtualised SQL 2008 server in a VMware vSphere 4.1 environment and have noticed some slow downs recently and am trying to pinpoint the cause.

The SQL Server VM is running on a LUN which is on our 6000e box. The VM's Memory and CPU usage are both fine but am unsure how to measure how well the disks are performing.

Within the vSphere environment i can see that the host that the VM runs on is running with a disk latency of 25-30ms (On Average) with a one time spike this week of 60ms

On the actual VM itself i can see that disk KBps is on average around 3,000 KBps with a maximum spike this week of 11,000 KBps.

Are these figures good, bad? I have nothing to compare it to and am not sure what the PS6000e is capable of

Any advice will be greatly received
"

Not horrible by any means.... Your SQL server sounds busy for sure though. Average latency is supposed to be kept around 15ms on the high side. Spikes are to be expected. When you say your experiencing slow downs? Like the users actually feel it on the applications side?

Thanks for your response. We have had SAP for a while now, first rolled out to Finance but in the last 6-7 weeks rolled out to Sales and Warehouse so we have added, probably around 30-35 users. We have a mixture of Windows XP and Windows 7 clients and most people have noticed that it can take a while to pull up a customer record, maybe as long as 20 seconds. Some people have their SAP client totally lock up for between 2-5 minutes before continuing as normal!! This doesn't happen all of the time and we have noticed that some people are running large reports which always slow the whole system down. The trouble is that is wasn't this slow when it was first rolled out, definately getting slower.

The company that has supplied it has said that it is a network issue or a disk latency issue. I am booking in a network analyst to investigate our network speed but if it was that i think we all would have noticed by now with slow logons and slow file saves.

With the disk latency i have no experience in measuring what the performance baseline should be, that is why i am grateful to anyone who can offer some expert advice

If the latency is consistently over 15ms what is the best way to resolve this? Buy an addional 6000 but with SAS disks? Are there any other things i should be looking at?

"Thanks for your response. We have had SAP for a while now, first rolled out to Finance but in the last 6-7 weeks rolled out to Sales and Warehouse so we have added, probably around 30-35 users. We have a mixture of Windows XP and Windows 7 clients and most people have noticed that it can take a while to pull up a customer record, maybe as long as 20 seconds. Some people have their SAP client totally lock up for between 2-5 minutes before continuing as normal!! This doesn't happen all of the time and we have noticed that some people are running large reports which always slow the whole system down. The trouble is that is wasn't this slow when it was first rolled out, definately getting slower.

The company that has supplied it has said that it is a network issue or a disk latency issue. I am booking in a network analyst to investigate our network speed but if it was that i think we all would have noticed by now with slow logons and slow file saves.

With the disk latency i have no experience in measuring what the performance baseline should be, that is why i am grateful to anyone who can offer some expert advice

If the latency is consistently over 15ms what is the best way to resolve this? Buy an addional 6000 but with SAS disks? Are there any other things i should be looking at?"

I am still not convinced of their explanation. Nothing in your latency pauses a user for the amount of time your users are complaining about.
You would see that 2000ms pause (20 seconds) if that was it.

Are there others hosts running on this array as well? This seems application specific.

You can use SAN HQ to measure your HDDs performance in depth.
Increased latency is due to SATA disks you might need to have may be SAS 10k to compensate this...ideally <<
For further resources you can go to Equallogic website (https://www.equallogic.com/support/resources.aspx)
Adding additional Equallogic will of curse increase IOPS and decrease Latency… but you need to check you network as well.