We have a number of windows guests (2008R2 - file server) that are using windows compression (for historical reasons) and within the last month have upgraded our environment, ESXi to 5.0 and the VNX to 5.32.000.5.015 - all our vmdk's are on block LUNs we dont use VNX FILE at all. Since the upgrade IO performance of the guests has decreased noticably from an end user perspective, eg: user experience, backup times, basic file copies. We have narrowed it down to only those guests using windows compression.
If I run Analyzer while they are doing a test copy I dont see anything particularly wrong with the stats except that the throughput is slow. The IOPS arent excessive, the service and response times are good, the queue length is not very long.
Setup is a VNX5500 with 3 tier FASTVP LUNs & 1TB of FAST Cache.
And the problem is occuring on multiple LUNs in the same pool, and at two different sites with near identical setups. (vBlocks)
The only thing I see thats noticably different since the upgrade is the % dirty pages of FAST Cache has changed dramatically since we upgraded. About 20% extra on both SP's.
I could just uncompress everything but would like to try and figure out why its happening.