Hosts keep "disconnecting"

[Cruicer]

How do I extent the timeout period for ESX host to check into vCenter.  I have two clusters that are not in the same physical location as my vCenter server, and it seems like once or twice a week they tend to lose connectivtiy to vCenter.  I suspect I have a slow network link to my vCenter server.

I can resent the management agent on the hosts I.E. service mgmt-vmware restart, and then they will stay connected for a bit of time.  And it is only those remote hosts that I have this issue with.

I have gone thru and removed the host from the cluster and re-added to force a re-install of the VPXA agent...but that didn't seem to help much.

[idle-jam]

is the pattern constant?

[Cruicer]

Yes...constant meaning at least once a week...normally on Mondays I need to go into each of those hosts and reset the management agent.

[idle-jam]

hmm, could it during the weekend that the switch does reboot itself or maybe there is an heavy traffic activity like backup? normally you would be able to see from the esxi host log if the network link is down or not. that would isolate that the switch may be down. this is one of the example ..

[Cruicer]

True..however it doesn't ALWAYS happen on Monday.  For example, this morning I came in and three of my host were in a "disconnected" state.  No rhyme or reason.  Again, only on these hosts which are remote from my vCenter server.  

[bulletprooffool]

First thing you should always do when you can't connect to - or if  there is an issue with your connection between vCenter and ESXi \ ESX is  to:

1) check DNS configuration on the ESXi server and your DNS server  that ESX points to making sure you have the appropriate entries
2) Check host files etc in /etc/hosts, /etc/resolve.conf, /etc/sysconfig/network and /etc/vmware/esx.conf files
2) try to disconnect and reconnect your ESXi host from your vCenter  inventory, this uninstalls and reinstalls the vCenter agent using FQDN  and then with IP address if FQDN didn't work
3) Try Restarting both the vCenter management agent on the ESX host and  the ESX host management agent. Learn how to do this here: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=100349...
4) If the above didn't do anything for you, it could be lost  connectivity to a LUN, which can cause problems with ESX (less now than  earlier versions ESX 2.x), connect to ESXi host directly with VI Client  and perform a rescan of your storage adaptors and LUNs.