Hi all, i cant think about an apropieted subject for the topic.
Here is the thing.
We have a Server with this specs
Windows Server 2008
8 x Intel Xeon L7555
32 GB Ram
RAID 5 with SAS disks. poweredge storage-
In the server we have
SQL Server 2008
15 GB for windows only.
The question is, can SQL server, in some way, affects the performance of all the storage.. in other words..
When we test the storage via Performance Monitor and HDTach, we have 22 MB MB/s for average read (disk) this is ridiculous becouse the hardware we have.
I ask here because we are encharged of sql server, no the hardware of the server, and i'm not a specialist hardware guy, but you dont have to be an especialist when see something like this.
I investigated performance monitor, with some Windows Server counters and I reach to the conclusion that we have a serious bottleneck problem.
Sorry for my out of practice english.. and what do you think about this (if the server is affected by disk performance)
1) Can you simply turn off SQL Server and rerun your IO tests? If SQL Server is doing active work it can DEFINITELY cause an IO test to see poor numbers!! You can completely overwhelm virtually any IO system with SQL Server.
2) Did you test this hardware BEFORE you put SQL Server on it (you should have).
3) Even if you have just 3 disks you probably should get more than 22MB/sec of throughput - certainly for sequential reads. But I have no idea about HDTach, nor did you provide what type of IO you were doing. Was it 4K random writes or 64K sequential reads or ??? Random writes with 3 disks in a RAID5 could really suck...
4) I cannot provide any guidance or recommendations without much more details about your actual IO configuration and the nature of of the tests you were doing.
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru at GMail