Hi All,
I've got 2 x ESXi 5.1.0 hosts (733933) in my environment connected to a iSCSI starwind datastore which has SSDs in a RAID array. It's very fast in that we've never had performance issues.
The datastore in question contains several virtual machines. The virtual machines are as fast as you'd expect, except for one. It's painfully slow, and I can't nail down why (IOMeter test below).
I've tried these techniques to figure it out:
- Run IOmeter multiple times of day to ensure it isn't some process on the problem VM that's causing issues
- Monitored disk queue length of the problem VM to make sure it isn't too busy
- Ensured all the virtual hardware parameters of the problem VM (disk controller type, CPU, RAM)
- Installed a fresh VM on this datastore to eliminate the datastore as a cause of the performance issue
- Checked the shares allocation of the problem VM to make sure it isn't getting pushed to the side under heavy load
I can't see anything that may cause this issue, anyone got any ideas?
The performance test:
