Frank and I have discussed this topic multiple times and it was briefly mentioned in Frank’s excellent series about over-sizing virtual machines; Zero Pages, TPS and the impact of a boot-storm. Pre-vSphere 4.1 we have seen it all happen, a host fails and multiple VMs need to be restarted. Temporary contention exists as it could take up to 60 minutes [...]
Ever since ESX 2.5 I have always been looking for cool free tools to monitor my hosts. I guess one of the oldest free tools out there is vmktree. Especially in the 2.x timeframe vmktree helped me out solving some weird performance issues. Back then vmktree was still dependent on vmkusage (who remembers that one?) but as of ESX 3.0 [...]
At VMworld I met up with the guys presenting the Storage I/O Control session, Irfan Ahmad and Chethan Kumar. As many of you hopefully know Irfan has always been active in the social media space (virtualscoop.org). Chethan however is “new” and just started his own blog. Chethan is a Senior Member of the Performance Engineering team At VMware. He focuses [...]
It seems that a lot of vendors are starting to update their firmware to enable virtualized workloads from the vStorage APIs for Array Integration, also known as VAAI. Not only the vendors are starting to show interest, also the bloggers are picking up on it. Hence the reason I wanted to reiterate some of the excellent details out there and [...]
During my flight from Boston back to the Netherlands I listened to the VMworld esxtop session “Troubleshooting using ESXTOP for Advanced Users, TA6720“. As always an excellent session with a lot of in-depth info. Most of it was already documented, however there were a couple of key points that I hadn’t documented yet. I just added those to my esxtop [...]
I have written multiple articles(1, 2, 3, 4) on this topic so hopefully by now everyone knows that Large Pages are not shared by TPS. However when there is contention the large pages will be broken up in small pages and those will be shared based on the outcome of the TPS algorythm. Something I have always wondered and discussed [...]
Today we had an interesting discussion on the VCDX mailing list. One thing I noticed a while back when I was randomly looking around in “esxtop” was a new field. The field is called ” RESVSTATS and can be enabled in all disk related displays(d, u,v). This will make troubleshooting storage related performance issues a bit easier as the SCSI [...]
