I set up an Ubuntu Server VM with 6 USB HDDs attached to it. All of them register as high speed devices in the VM, but have full-speed performance.

I would expect better than 2.5MB/s throughput to them, even with the slower mobo (Asus E35M1).

Is poor USB HDD performance a known thing with ESXi? It seems I can I/O to a single drive at about 12-15MB/s, or 1/6th of that to each - so the throughput to the whole USB system seems to be limited.

Any thoughts?
Thanks