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vSphere Bugs & Minor Irritations

I’ve recently reported a couple of annoying bugs to VMware. Both have been around for a long time, almost certainly since the days of Virtual Center 2.0, maybe even earlier.

  • If a VM has nothing in the “Notes” annotation, vCenter displays the “Notes” from the previously selected VM instead.
    So if you have a machine with a note saying “Delete after 1st Jan 2011”, and you then view the summary of a machine with no note set, it’ll display the “Delete after 1st Jan 2011”. That could be bad…
    The problem only occurs if the VM has never had any Notes annotation. If you set one and then remove it, it shows the blank note correctly.
    **UPDATE**This appears to be fixed in 4.1 U1 – it only seems to affect VMs which were deployed without notes under VirtualCenter 2.x.
  • When deploying a VM from a template, the Tasks & Events history doesn’t correctly name the template from which the VM was deployed.
    As you can see in the example image, vCenter lists the deployed VM name instead of the template. 

Click for full size

** UPDATE ** VMware have acknowledged this as a bug but it will not be fixed until vSphere 5, later this year.

And there’s a cosmetic thing which winds me up. I haven’t reported it as a bug but if anyone from VMware reads this, maybe they can have a word. It’s really trivial….

Send Ctrl-Alt-del“. What has “del” done to deprive it of a capital “D”?

VMware Fusion also has a “Send Ctrl-Alt-Del” menu option but it gets the capitalisation right. I can only offer this as proof that Macs are better than PCs… or something.

vSphere HA Slot Sizes

vSphere HA slot sizes are used to calculate the number of VMs that can be powered on in an HA cluster with “Host failures cluster tolerates” selected. The slots size is calculated based on the size of reservations on the VMs in the cluster. HA Admission Control then prevents new VMs being powered on if it would not leave any slots available should a host fail.

The slot size for a cluster can be seen by going to the Summary Page for the cluster and clicking the “Advanced Runtime Info” link in the HA box.

If none of the VMs have CPU or RAM reservations, a default of 256MHz and 0GB is used.

The slots per host is derived by taking the total available CPU/RAM for the host and dividing by the slot size. Some CPU is reserved for the system so it will usually be a little lower than the full amount. So a host with 2xquad-core 2.4GHz CPUs (total 19.2GHz) and no VM CPU or RAM reservations has 73 slots and will only allow 73 VMs to be powered on if the cluster has two hosts and is set to protect against a single host failure.

Obviously this allows a very minimal amount of resource for each VM, so either reservations should be set for each VM, or slots size can be manually adjusted (see the VMware vSphere Availability Guide (pdf) for full details).

Note that the slot size is used for admission control calculations only. It has no direct effect on the resources available to VMs should an HA event occur.

There is a VMware Knowledgebase article (1010594) which  has some details of the difference in VI3 and vSphere 4.x.