VMware ESX 3.02, c-Class Enclosures & HP EVA 8x00


Im hoping someone will be able to assist me with regards to read and write latency.

I have been doing some baseline storage reports for the EXA's that host our VMware Virtual Desktop Infrastructure.

The setup I have is HP c-Class enclosures running VMware. 2 x 8 Server clusters per enclosure. Connectivity and Server hardware are BL485 G5 Servers - HBA - mds9124e internal - mds9124e external - (NPV mode) - Core Switch - Storage Port (EVA) - EVA 8100.

Load is evenly distributed across all storage processor ports which the Controller Status Performance Object is showing. 1 controller is working slightly more as the BFS volumes all go through Port 1 on Controller A due to the installation LUN must be the lowest-numbered of the LUNs available to the physical host.

Do we have any figures as to limitations on the following EVAPerf counters?

Host Port Statistics Performance Object

Read Req/s & Write Req/s

Read MB/s & Write MB/s

Read Latency & Write Latency

Av Queue Depth

Queue Depth Readings are around 1-2 which looks to be fine, host port Stats look to be fine with utilization on the paired controllers below 50%

The issue where I need assistance is the Average Read Latency & Average Write Latency, I understand that Aa average Read Latency < 15ms and Average Write Latency < 5 ms should be acceptable for most workloads, does this also cound for VDI's?

I am seeing the readings below, read latency is fine, however the write latency is above the 5 (ms) recomendation, now this recomendation isnt set in stone and so if there are any concrete acceptable / not acceptable figures out there supplied by HP or VMware I would appreashiate a benchmark figure.


Average Read Latency (ms)

Average Write Latency (ms)







Kind Regrads


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