http://www.vmwarewolf.com has a blog post titled : ESX disconnects randomly or when doing VI client tasks from VC, task randomly timeout after a long idle time
I like to link posts that I Feel are important for people to see, hence my reasoning.
Thanks to vmwarewolf
here’s a new problem a few customers have reported whereby-
- ESX disconnects randomly from Virtualcenter
- ESX disconnects when performing VI Client tasks from Virtualcenter.
- Tasks randomly timeout after a long idle time
- "An error occurred communicating to the remote host" pops up.
This only refers to Update 3. This issue seem to be affecting customers with firewalls using stateful inspection, such as a Juniper ISG 2000, Software Revision 6.1.0R3.
The problem occurs because of SOAP timeouts, and this behavior did not exist in VC 2.0.x or 2.5 GA, as they used a different mechanism to communicate with ESX.
A knowledgebase article (1008142) is due out imminently on this problem.
- Create a dummy VM on each host (e.g. 16 MB RAM, no disk, no network).
- Set CPU affinity to the last core to prevent VMotion.
- Create a new Scheduled Task that performs:
- Change power state: Power-on dummy VM. Every hour, on the hour.
- Create another Scheduled Task that performs:
- Change power state: Power-off dummy VM. Every hour, 30 minutes after the hour.
Meanwhile, I know Engineering is aware of this issue and actively investigating it.
Full Post http://www.vmwarewolf.com/esx-disconnects-randomly-or-when-doing-vi-client-tasks-from-vc-task-randomly-timeout-after-a-long-idle-time/