I have built my vSphere environment on HP G7 blade servers with Flex10 virtual connect. first couple of weeks were perfect. after some time i started having performance issues with all my VMs (including vCenter). response was slow when accessing VMs, high network latency, and large set of consequent errors reporting that paths to all datastores frequestly change power status.
I removed two hosts from the vDS for testing sake, and waited to see if the problem is isolated, but the problem reamined.
Then I opened a case with the FC fabric vendor (EMC), they rercommended changing the auto-negotioation of the switch ports from "Auto" to "Static". this did solve the problem, and the datastore connectivity message disappered for a while. today, I intended to return the two hosts that I removed from the vDS back, a couple of minutes later, the message appeared again and the same performance issue affecting the VMs surfaced.
any clue would be appreciated.
P.s. I will attached relevant logs by tomorrow.