I need to look in to an SQl LUN performance issue, the LUN is served by an EMC CX4-240 SAN.
my issue is that SQl performance is poor, the SQl server is robust enough for the workload i.e. CPU utilization is at about 25% Memory 53%.
however on the storage side when I look at MS counters using prefmon.exe most of the counter like queue, Disk transfer per/sec average disk bytes disk write are all at 100% at all times.
I ran an SQl backup to NULL so I could estimate my storage performance and the the process completed with the speed of 49.5 MB/sec.
I ran the same SQL backup to NULL on a lab system on an ESX server and storage on the same ESX at a much faster speed of 120.3 MB/sec.
how can I pinpoint the source of this performance bottleneck, the SAN people are telling me that the SAN is solid and all I can see on the SQl server side points to disk issue.
any help would be appreciated.