I just received an email from one one of my readers, Mike Laskowski, he wanted to share the following with us: I have over 100+ LUN’s in my environment. Round Robin is officially supported on ESX4. In the past we had a script that would manually load balance the LUN’s across FAs. ESX4 has a different way to balance the [...]

The last couple of weeks I’ve seen all these performance numbers(most not publicly available though)  of vSphere, one even more impressing than the other. I think every one will agree that the latest one is really impressive, 364.00 IOPS is just insane. There’s no load vSphere can’t handle, when correctly sized of course. But something that even made a bigger [...]

Most people heard about this by now, Technet and MSDN are running on Hyper-V. As Microsoft states, an enterprise ready solution. Both Technet and MSDN crashed this week, or should we say Hyper-V just doesn’t cut it. Check this Youtube  movie that clearly shows what happens when VMs are stressed: A professional associate of mine shared screen captures of a [...]

I was just reading a discussion on the VMTN community on CPU affinity. The general opinion of the Experts is “Don’t use CPU affinity”. I fully agree with them, ESX is more than capable to handle the scheduling on it’s own with just a limited overhead. And like Ken Cline also stresses it could harm performance because of NUMA load [...]

We just had a very good and interesting VMTN Podcast on virtualized MS SQL performance and best practices. One of the questions was about disk performance. Hemant Gaidhan talked about esxtop and how to discover possible performance issues, and specifically mentioned latency. I’ve never really looked into this section of esxtop and did a quick search and of course the [...]

A while back I wrote an article on checking your disk alignment and even changing the disk alignment from the service console. Since then a lot of people asked me for the exact link, because I don’t have a now.NetApp.com account I wasn’t able to provide it. Today I received an email from the developer, Eric Forgette, with a link [...]

The next version of ESX has a totally different architecture for storage. The new architecture is called “Pluggable Storage Architecture”. For my own understanding I wanted to write down how this actually works and what all the different abbreviations/acronyms mean: PSA = Pluggable Storage Architecture NMP = Native Multipathing MPP = Multipathing Plugin PSP = Path Selection Plugin SATP = [...]