Running Domino on Windows 2003 on ESX?

Do you run Domino 7.0.x, 8.0.x or 8.5 on Windows 2003 on VMWare ESX?  If so, you might wish to check the performance you’re seeing from the Domino HTTP stack:

Poor performance of Domino HTTP server on VMware ESX 3.0 and 3.5
 Technote (troubleshooting)
While VMware ESX is a supported hypervisor for Domino and Domino based applications, several customer have reported poor performance of Lotus Domino HTTP on Windows 2003 on VMware ESX. The symptoms are flat CPU utilization (regardless of the number of vCPU assigned to the VM, 1, 2 or 4 vCPUs presents identical performance), low memory utilization and very high response time to Web users requests with moderate load (more than a few users hitting the server).

If the same application is accessed with the Notes client, the performance is acceptable and the application appear to function properly.
The cause of this issue is currently unknown. IBM and VMware are working to identify the source of this problem. Customers that open a SR (service request) with VMware can reference VMware PR (Problem Report) 318726.

IBM Lotus Support has confirmed the problem and verified it is not introduced by a Domino server misconfiguration. In fact, the same settings allow the Domino server to serve HTTP requests in a timely fashion and support heavy load when running on a physical server, while response time increases considerably when the same Domino server runs in a Virtual Machine on VMware ESX 3.0 and 3.5.

So, if you’re seeing poor or inconsistent performance from Domino HTTP, this might be the cause.

My advice would be not to run Domino on 32-bit Windows 2003 server if at all possible, whether on VMWare or on physical machines.  Make the move to Linux to get the very best reliability and performance from your Domino VM infrastructure.

(Thanks to @pdsmith for the tip…)