I run two Clusters between two different Datacenters and networks. One of them (the fast one) is running ESXi hosts with 4.1 version and the other one (slow) is running ESXi on 4.0 version.
One of the clusters I have lots of more VMs than the other and customers are not complaining of storage performance. On the other cluster I have much less VMs and customers are complaining because of storage performance.
When I start to deploy a template at the same time between both Clusters, I see that the cluster without performance issues goes much much faster than the other.
The fast cluster is using 15x450GB SAS disks in one group only of RAID 5 plus one hot spare. The other (slow) cluster is using 15x300GB SAS disks one one group only of RAID 5 plus one hot spare. I know that one group only is not the best way to have performance after reading some MD3000i documents, although I cannot do anything at this time. The weird thing is that one of the cluster is running without any issue and the other is having performance issues.
How can I check on the new vSphere version my storage performance ? Maybe one of the VMs is killing all the storage I/O ? How can I check that ? I couldnt find it on VMWare manual.
If its not any VMs can it be any faulty disk or a slower disk in the storage degrading all the performance ? I dont remember if I have any 10K disks in the storage. Is it possible to check if any of the disk on the array is degrading performance ? If so, how ?