Week 22 already. Almost half way down 2010. Next week the Fifa World Cup starts. For those of you, probably Americans, who don't have a clue what it is about: World Cup Soccer. And yes this is the most widely viewed sports event there is and the cool thing about it is that you get to watch sports for 45 minutes in a row before you have a commercial break! Anyway, there's one thing left to say before I will list this weeks Top 5: GO HOLLAND!

  • Cody Bunch – The Math Behind the DRS Stars
    In our particular case, not much to look at, as well, she is seemingly a well balanced cluster. However let’s work through the formula with the assumption that we have a 2 node cluster and a standard deviation of 0.282 (the “target” from above): 6 – ceil(0.282 / 0.1 * sqrt(2)).
  • Eric Sloof – Caveat when using – Percentage of cluster resources reserved as failover spare capacity
    I think everyone knows the three admissions control policies which can be enforced on a VMware HA Cluster.  If you are using the default “Host Failures Allowed” policy, you must keep in mind that the largest virtual machine reservation will decide how big your cluster slot size is going to be. In most cases when you are using reservations that differ, I would prefer to use the “Percentage of cluster resources reserved as failover spare capacity”. But be careful, I’ve pulled two quotes which warn us for scattered resources and the need to set restart priority on large virtual machines.
  • Simon Long – VMware ESXi 4 Log Files
    This is the ESXi Host Agent log. It contains information on the agent that manages the ESXi Host and it's VM's. I don't tend to use this log as much as I used to with ESX, purely because it has been amalgamated in the message log. If you are troubleshooting a Host issue and don't want vmkernel logs getting in the way, this is the log for you. The log entries are time stamped (using UTC timezone) which is pretty handy when looking back to see what happened when an error occurred or something failed.
  • Arnim van Lieshout – PowerCLI: Reset CPU and Memory Limits
    Today I noticed a memory limit on a vm. After investigating my environment using the vEcoShell and the Community PowerPack, I found more vms with memory limits set. It turned out that there was a template which had the limit set. I could easily reset all limits using the GUI, but I thought I rather do it with PowerCLI. Alan Renouf did a post already on a oneliner to reset all cpu and memory limits back in july 2009. After trying that code I found it rather slow. If you want to speed up things in PowerCLI you need to use the Get-View cmdlet. After some digging in the vSphere API Reference, I came up with a different peace of code that is much faster.
  • Duncan Epping – esxtop -l
    As most of you know esxtop takes snapshots from VSI nodes (similar to proc nodes) to capture the running entities and their states. The rate in which these snapshots are taken can be changed with the “s”. The default setting is 5 seconds and the minimum, which most people probably use, is 2 seconds. This means that every entity (worlds, for instance a virtual machine) and the associated info is queried again every two seconds. As many of the metrics shown in esxtop are calculated based on the difference of two successive snapshots, e.g. %USED (CPU), esxtop just rereads all the info(all entities and all values) and calculates the values of the metrics.