My ramblings about all things technical

Leave a comment

VMware Knowledge Nuggets – Percentage of Host Resources Admission Control

As started and introduced in my introductory posting around the VMware Knowledge Nuggets I am posting compact VMware knowledge nuggets which I hope will show people some unknown features or things they need to think about around choosing features and maybe even get some good discussions going via the comments section.


Using Percentage Based Admission Control and the usage of das.vmMemoryMinMB and das.vmCpuMinMHz.

This discussion stemmed  from the twitter discussion I had with Ed Grigson a few weeks back as mentioned in my first posting (albeit a tangent off of it) . I commented that even if you use percentage based admission control it is still a good idea to configure the das.vmMemoryMinMB and das.vmCpuMinMHz advanced settings to provide a better idea when HA is doing the math for admission control and prevent overcommitment with a specified minimal amount of resources for each virtual machine.


Rather than re-cover what has been done and explained so well,  the following two postings from Duncan Epping and Josh Odgers respectively cover it perfectly


Using das.vmmemoryminmb with Percentage Based admission control

Example Architectural Decision – VMware HA – Percentage of Cluster resources reserved for HA


Certainly something to keep in mind when doing designs and even something that you may determine is good to add to your existing environment. Although remember that admission control is not about resource management as described really well by Duncan Epping in his article here. Funnily enough I think a discussion I had with Duncan at the 2011 Europe VMworld around a customer using reservations with percentage based admission control for resource management caused him to create the posting.