VMware iSCSI connection issue

[mrbios]

Got a bit of an issue with a vmware server, the iSCSI connection to it was only created today, the VMware server is running ESXi 4 version 219382

The issue:
Installing Server 2008R2 it'll get somewhere between 90% and very near finishing the install then the iSCSI will completely drop out, link status shows as dead

I'm guessing the iSCSI would drop out wether i was installing an OS or not as it seems like it's doing it after a set amount of time, anyone have any ideas? only got 3 servers to upgrade until i can up the domain functional level (yay)

 

[paradigm]

What is the iSCSI target? A dedicated SAN or a homebrew of some type?

 

[mrbios]

a dedicated SAN, which has many other iSCSI links to other servers some physical some VMs without a problem

Only difference being here is that this server it keeps dropping off of is located accross a trunked fibre whereas all the others are in the same rack as the SAN itself

 

[paradigm]

Well first things first, I'd be looking at your fibre. How is the SAN connected to the switch that has the trunked fibre link? What switches are at either end of the fibre? What encapsulation is being used?

Much more information needed on the physicality of the network.

 

[mrbios]

Well first things first, I'd be looking at your fibre. How is the SAN connected to the switch that has the trunked fibre link? What switches are at either end of the fibre? What encapsulation is being used?

Much more information needed on the physicality of the network.

the SAN is connected to the switch via a 1GB connection, switch at one end is a HP4108GL (which is at the absolute limit of it's routing abilities, 8206zl coming in about 2 months) and 3400cl at the other end

Done a bit of hunting around and it seems theres a fairly common issue with iSCSI LUNs dropping off when under heavy load on vmware, not sure what the cause is this time though, i wouldn't call loading an ISO and VM from iSCSI heavy load though