I was just reading some of the comments posted today and Marc Sevigny, one of the vSphere HA developers, pointed out something which I did not know. I figured this is probably something that many are not aware of so I copied and pasted his comment: Another thing to check if you experience this error is to see if you have [...]
I just wanted to point out a couple of changes for HA in vSphere 5.0 with regards to admission control. Although they might seem minor they are important to keep in mind when redesigning your environment. Lets just discuss each of the admission control policies and list the changes underneath. Host failures cluster tolerates Still uses the slot algorithm. Major [...]
I was reading some threads on the VMTN forum and noticed a question on an advanced HA setting called “das.slotMemInMB”. The setting is briefly mentioned in my deep-dive, but after re-reading the section I think I could have been more clear in describing what is does, how it works and when to use it. Of course anything that goes for [...]
One of the things that has always been missing from VMware’s High Availability solution stack is application awareness. As I explained in one of my earlier posts this is something that VMware is actively working on. Instead of creating a full App clustering level VMware decided to extend “VM Monitoring” and created an API to enable App level resiliency. At [...]
Early 2009 I wrote an article on the impact of Primary Nodes and Secondary Nodes on your design. This was primarily focussed on Blade environments and basically it discussed how to avoid having all your primary nodes in a single chassis. If that single chassis would fail, no VMs would be restarted as one of the primary nodes is the [...]
I was discussing something with one of my former colleagues a couple of days ago. He asked me what the impact was of running VMware View in an environment without HA. To be honest I am not a View SME, but I do know a thing or two about HA/vSphere in general. So the first thing that I mentioned was [...]
The amount of retries is configurable as of vCenter 2.5 U4 with the advanced option “das.maxvmrestartcount”. My colleague Hugo Strydom wrote about this a while ago and after a short discussion with one of our developers I realised Hugo’s article was not 100% correct. The default value is 5. Pre vCenter 2.5 U4 HA would keep retrying forever which could [...]
