VMware has just released an advisory for the Broadcom bnx2x Inbox drivers in ESX 4.1 which will affect HP Servers including blades.

ESX/ESXi 4.1 with Broadcom bnx2x Inbox driver version 1.54.1.v41.1-1vmw experiences a loss of network connectivity and a purple diagnostic screen

http://kb.vmware.com/selfservice/search.do?cmd=displayKC&docType=kc&externalId=1029368

The resolution (which is only a workaround) says it manifests itself when using the IP Checksum feature which is on by default on ESX and ESXi 4.1. This feature moves the checksumming (if there’s such a word) from the OS stack to the adapter and can cause a driver or firmware panic.

Now, the question is, is this a serious enough problem to immediately go out and disable checksumming?  The KB doesn’t say but this looks like it could be a serious issue.

Hopefully some more information will be forthcoming from VMware / HP / Broadcom but at least you’ve been warned!