I am running VMWare ESX 4.1.0, 260247 on an intel DX58SO motherboard with a HighPoint 4310 raid controller.

The server has 2 velociraptor drives in RAID 1 and 2x WD black 2TB drives in RAID 1 as well.

The rig has been working properly for over a year, but yesterday we started noticing extremely bad disk IO on the vm's at random. Regardless of which raid the vm was stored in, we recorded 1MB/s reads.

If we restart the vm, performance goes back up to 80MB/s on reads, but in a matter of hours it goes back down to 1-3.

We've tried just leaving 1 vm on, and still experience the same issue.

I've ran into this problem before with ESXi as well, and have never found a solution. It seems to happen over time.

Thanks in advance for any feedback.