DELL PS4100xv and SAN HQ acceptable Disk performance

Question

Hi,

I have a Dell PS4100xv with 12x 600 GB 15K SAS drives configured at RAID 6.

Three (3) R420 servers are connected via 2x Power Connect 6224 (stacked).

I'm running ESXi 5.1 U1 with a mix of SQL VMs, File servers and Proxy servers.

What are acceptable values for a healthy EQL in terms of latency, disk queue, IOPs and etc?

Just recently, I transferred a VM to the PS4100XV. The VM has very sluggish behavior when operating from the Dell EQL. It's SQL Server. Got a lot of users complaining on the sluggish behavior.

I need to determine, if I have a problem on my PS4100xv in terms of performance before I start troubleshooting the VMs and ESXi hosts.

These are the readings taken from SAN HQ for the last eight hours.

If, I got this right this my own analysis

Disk Queue is ok, since its consistently @ 0. EQL can handle the load and nothing is pending.

IOPs is ok, since base on the RAID Evaluator my array should support 1500 IOPs. Current reading is at 742 IOPs only.

Latency for write is ok because it's at 13 ms and does not even approaches 20 ms.

Latency for read , do I have a problem ? It is consistent above 20 ms. Hovers around 25 ms to 40 ms. But does not exceed 40 ms.
For IO Rate & IO size, I have no idea if this is a good indicator. What are acceptable values?

Disk Queue Depth:	zero (0), the graph show its flat at zero.
Average READ IOP:	625
Average WRITE IOPS:	117
Total Average IOPs	742

Average READ Latency	30 ms (20 ms to 40 ms)
Average Write Latency	13 ms (straight line @ 13 ms)
Weighted Average	28 ms

Average IO Rate Reads	26.41 MB/sec
Average IO Rate Write	2.26 MB/sec
Total	28.67 MB/sec

Average IO size READ	43.30 KB
Average IO size WRITE	19.91 KB
Weighted Average	39.62 KB

There are no retransmit packets and network utilization is at 3% only.

Would really appreciate any inputs and recommendations.

What are acceptable values for a healthy EQL in terms of latency, IOPs, disk queue and etc?

Thanks,

Paul

hkraal · Answer

I find your latency to be somewhat high, this can (strange enough) be due low IO load but as the performance experience isn't that great I would suggest to seek futher.

For your idea; we've an 6100XV with 24 hour averages being: iops 1621 (46% read / 54% write), 16 KB IO size, 8.9 ms read latency, 2.4 ms write latency. 25 MB/ps troughput.

Our latencies now are only half of what they used to be before I disabled delayedAck and LRO. I certainly would recommend to check those out in the various guides.

EDIT: our unit has 24x 500GB 15k rpm disk in raid-10 and is rated (in SanHQ) for ~4000 IOps

ZianPaul · Answer

Hi. Donald,

Thanks for the suggestions. Been following the document since deploying my first EQL.

By the way I'm from the Philippines, I'm not sure will Dell Philippine help me on performance related issues. They assist me on hardware problems only. I got ProSupport.

Round Robin is configured. But I don't use the 3 IOs per path.

---> my other ESXi hosts are behaving ok. no complains from user.

Delay Acknowledgement is Disabled

Jumbo Frame is enabled with port binding

Login time out is set to 60 seconds.

I haven't tried changing the virtual SCSI adapter, will try doing this.

Haven't also disabled LRO.

is this acceptable readings for EQL?

Average READ Latency 30 ms (20 ms to 40 ms)

Average Write Latency 13 ms (straight line @ 13 ms)

Weighted Average 28 ms

Thanks,

Paul

EqualLogic

DELL PS4100xv and SAN HQ acceptable Disk performance

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