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by Duncan Epping

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ESX

New ESX(i) 3.5 patches available

Duncan Epping · Apr 30, 2009 ·

Normally I would give you guys a nice overview of the patches + KB articles but I’m on a holiday this week with limited access to wifi. Because I’m typing this on my blackberry this post will lack the details, feel a bit like Rev. Run ;-), but you guys know the drill anyway.

In total 11 new patches (9 for ESX and two for ESXi) are up for download. Make sure to read the accompanied KB articles first and of course test the patches before implementing!

Have fun,

CPU Affinity…

Duncan Epping · Apr 28, 2009 ·

I was just reading a discussion on the VMTN community on CPU affinity. The general opinion of the Experts is “Don’t use CPU affinity”. I fully agree with them, ESX is more than capable to handle the scheduling on it’s own with just a limited overhead. And like Ken Cline also stresses it could harm performance because of NUMA load balancing for instance.

Something that’s often overlooked though when one does CPU affinity is that people tend to give the VM vCPUs a 1:1 relationship with host cores. In other words a VM with two vCPUs will be pinned down to two cores on the host.

This does make sense doesn’t it? No it actually doesn’t. There’s more to a VM than just it’s vCPUs. I would like to refer to page 132 of the Resource Management Guide, aka HA-DRS Bible. In short, besides the vCPUs there are several VM associated threads that need to be scheduled as well. When affinity is set these threads, or worlds as VMware calls them, will be scheduled on the assigned cores. You can imagine that when you use the vCenter client to manage the client these threads(Video / Keyboard / Mouse / CD-Rom etc) will need to be scheduled on the same set of cores as the vCPUs need to be scheduled on… If you have a two vCPU VM and want to use CPU affinity pin it down to at least three cores! Before you start assigning cores to your VM also read the bulletpoints on page 133 why you shouldn’t.

The CPU affinity setting for a virtual machine applies not only to all of the virtual CPUs associated with the virtual machine, but also to all other threads (also known as “worlds”) associated with the virtual machine. Such virtual machine threads perform processing required for emulating mouse, keyboard, screen, CD‐ROM and miscellaneous legacy devices.

In some cases, such as display‐intensive workloads, significant communication might occur between the virtual CPUs and these other virtual machine threads. Performance might degrade if the virtual machineʹs affinity setting prevents these additional threads from being scheduled concurrently with the virtual machineʹs virtual CPUs (for example, a uniprocessor virtual machine with affinity to a single CPU, or a two‐way SMP virtual machine with affinity to only two CPUs).

For the best performance, when manual affinity settings are used, VMware recommends that you include at least one additional physical CPU in the affinity setting in order to allow at least one of the virtual machineʹs threads to be scheduled at
the same time as its virtual CPUs
(for example, a uniprocessor virtual machine with affinity to at least two CPUs or a two‐way SMP virtual machine with affinity to at least three CPUs).

Export and import DRS affinity rules

Duncan Epping · Apr 23, 2009 ·

I just noticed this awesome work by LucD. He developed two scripts which can import and export DRS affinity rules. Especially in large environments or environments that have multiple affinity rules this is an excellent solution. Take a look at the link above for more details. Luc posted the script half way down the topic in text but also added a modified version at the bottom. The VI Toolkit at it’s best… or should we call it PowerCLI these days?

Bluebear Kodiak, what’s up?

Duncan Epping · Apr 22, 2009 ·

I still receive a lot of beta invitation requests while it has been really quiet around Bluebear Kodiak over the last couple of months. (I did a (p)review a while back) I just received an email that a brand new version of the Kodiak beta is about to be released. I already received the Air file but haven’t been able to test it yet. But Matt Miller of Bluebear uploaded a demo video just which shows some of the new features and I must say it really looks slick.

If you are still looking for an invite, I received another 50 and it’s on a first come first serves base. Just click here for an invitation.

(update: the invites don’t seem to be working, I will ask Bluebear to fix it asap.)

VMware vSphere Health Check Report v1.0

Duncan Epping · Apr 22, 2009 ·

I already blogged about this awesome healthcheck script by William Lam a couple of times and it just has been updated to version 1.0. The following details have been added to the already extensive list:

  • New New licensing format/summary
  • New EVC Enabled information
  • New Cluster VM monitoring
  • New Cluster Host monitoring
  • New # of VMotions within a cluster
  • New Datastore uncommitted info
  • New CPU power management info
  • New VM info (FT, Record/Replay, Clean Poweroff)
  • New Host IPv6, FT, SSL Thumbprint
  • New Host Profiles
  • New vApp information
  • New Distributed vSwitch information

Check the detailed output example William uploaded recently.

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About the Author

Duncan Epping is a Chief Technologist and Distinguished Engineering Architect at Broadcom. Besides writing on Yellow-Bricks, Duncan is the co-author of the vSAN Deep Dive and the vSphere Clustering Deep Dive book series. Duncan is also the host of the Unexplored Territory Podcast.

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