Recent Posts

Admission control: "used slots" exceeds "total slots"

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By Duncan Epping, Principal Architect. On the VMTN forum today someone asked how it was possible that the “used slots” exceeded the “total slots”. This is what their environment showed in vCenter: HA Advanced Runtime Info:Slot size                          4000Mhz                                   4 vCPUs,                                   4232MBTotal Slots in Cluster             16Used Slots                         66Available Slots                    0Total Powered on vms in Cluster    66Total Read more...

vSphere HA isolation response… which to use when?

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By Duncan Epping, Principal Architect. A while back I wrote this article about a split brain scenario with vSphere HA. Although we have multiple techniques to mitigate these scenarios it is always better to prevent. I had already blogged about this before but I figured it wouldn’t hurt to get this out again and elaborate Read more...

Going to VMworld? Meet the Technical Marketing Team!

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By Duncan Epping, Principal Architect. Many have asked me if I could make a list of all the people from the VMware Technical Marketing team responsible for vSphere and the Cloud Infrastructure Suite (or components of) who are presenting at VMworld. I have listed everyone below who is presenting and where applicable have added links Read more...

vSphere HA admission control calculation for memory

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By Duncan Epping, Principal Architect. Someone asked me today how the calculation is done for memory when the "Percentage Based" admission control policy was selected. As hopefully all of you know by now, the percentage based admission control policy does not work with fixed slot sizes. (More details to be found in the Availability Guide Read more...

VMware Workstation Tech Preview 2 available

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By Duncan Epping, Principal Architect. I just noted on twitter that VMware Workstation Tech Preview 2 was released. I know this blog is not about Workstation but about vSphere, despite that I feel it is important enough to mention. One of the reasons for it is the fact that with VMware Workstation TP2 you can: Upload Read more...

vSphere Metro Storage Cluster white paper ebook formats available

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By Duncan Epping, Principal Architect. I just received the mobi and epub version of the vSphere Metro Storage Cluster white paper. These versions should be compatible with the various types of e-readers including your iPad. VMware vSphere Metro Storage Cluster (VMware vMSC) is a new configuration within the VMware Hardware Compatibility List. This type of Read more...

vSphere Metro Storage Cluster white paper released!

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A brand new white paper was just published. This white paper was written by Lee Dilworth, Ken Werneburg, Frank Denneman, Stuart Hardman and I. It is a white paper on vSphere Metro Storage Cluster solutions and specifically looks at things from a VMware perspective. Enjoy! VMware vSphere Metro Storage Cluster (VMware vMSC) is a new configuration Read more...

HA split brain, which VM prevails?

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By Duncan Epping, Principal Architect. I received a question on twitter last week around HA split brain scenarios. Let me give an example first of when a split brain scenario could occur: Isolation response = leave powered on iSCSI / NFS storage When the above two requirements are met and a host in your cluster Read more...