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.
based on the EMC stats check what is running on sql (probably sql backups):
if backups try to use backup compression, different times of the backup execution maybe also you can check if your sql server has regularly running DB maints jobs: reindex; checkdb; update stats, etc..
see what queries are running when you got the problems -- you may have some select into (for example) and need to tune tempdb ; maybe you need to put your DBs on fast drives (fiber)..
check with EMC what you have? check the running code that may need optimization, check your sql server configuration
\setup..
and post what you found