I've been experiencing this issue for a couple of months now where my ESX hosts lose connectivity with my iSCSI SAN vmfs volumes.
As a results the ESX hosts enter a nonresponsive mode the associated VMs disconnect and the only remedy is to reboot the host.
This issue happens randomly . I have escalated this issue with VMWare but I haven't had any solution to the issue yet.
I see no errors on my switches and there are no hardware issues as well. My SAN infrastucture is solid and there are 2 paths for every vmfs volume.
Did anybody else experienced a similar issue?
edit: Here are some more details:
The iSCSI SAN software is Datacore Sanmelody 220.127.116.11 running on 2 HP Proliant G5 servers. The storage attached to each of the servers is an HP MSA70 and all the iSCSI SAN Volumes that are presented to my 4 ESX hosts are mirrored.
I have two iSCSI swithces HP Procurve 1800G-24 that are trunked together. My SANLELODY servers are using NC360T NICs. I team two NICs and have one cable connecting to each iSCSi switch. Each ESX server uses two NICs as well for the iSCSI Network.