Mport OVF from vSphere ESXi to VMware Workstation 7 Problem

Have you tried calling Dell support? Such issues are usually resolved very quickly

I suspect that you're using consumer-grade drives for your storage? If so, these have onboard error recovery systems which will stall the volume while error recovery is being attempted. When this occurs, all storage serving can be delayed for a considerable period of time (10+ seconds).

In enterprise-grade drives, this 'feature' is disabled or never included, on the assumption that error recovery will be handled at the RAID-array level (RAID's implicitly assumed for enterprise deployments). For example, Western Digital refers to this feature (or removal of a feature!) as TLER - Time-Limited Error Recovery. In practical terms, it means a drive with TLER enabled won't stall out for an extended period of time to perform sector recovery/remapping/whatever.

So if you're running consumer drives, there's a fair chance you've hit an error on one of your disks, and it's repeatedly stalling out while it attempts to recover.

Solutions for this may be a bit tricky - I don't know if any third-party disk error scanners will support VMFS, and wouldn't risk pulling the disks and scanning them with ANYTHING, unless completely sure it won't trash the volume.