Comments on: The Truth About Hyper-V Memory Overcommit http://www.vcritical.com/2010/01/the-truth-about-hyper-v-memory-overcommit/ Informed Virtualization Criticism Fri, 30 Jul 2010 12:54:25 -0700 http://wordpress.org/?v=2.9.1 hourly 1 By: Hypervisor Wars : memory overcommit - Hypervisor.fr http://www.vcritical.com/2010/01/the-truth-about-hyper-v-memory-overcommit/#comment-9691 Hypervisor Wars : memory overcommit - Hypervisor.fr Fri, 19 Feb 2010 13:04:19 +0000 http://www.vcritical.com/?p=2216#comment-9691 [...] que Microsoft continue à prétendre que le mécanisme de memory overcommit est dangereux pour votre production (mais, certainement comme pour Vmotion, lorsque cette fonction sera disponible sur Hyper-V, ce sera [...] [...] que Microsoft continue à prétendre que le mécanisme de memory overcommit est dangereux pour votre production (mais, certainement comme pour Vmotion, lorsque cette fonction sera disponible sur Hyper-V, ce sera [...]

]]> By: Post-R2 release of Hyper-V may include memory overcommit - Dynamic Memory | VCritical http://www.vcritical.com/2010/01/the-truth-about-hyper-v-memory-overcommit/#comment-9631 Post-R2 release of Hyper-V may include memory overcommit - Dynamic Memory | VCritical Tue, 02 Feb 2010 04:52:43 +0000 http://www.vcritical.com/?p=2216#comment-9631 [...] like I was on to something a few weeks back when I showed how Microsoft had tried — but failed — to implement a feature that would [...] [...] like I was on to something a few weeks back when I showed how Microsoft had tried — but failed — to implement a feature that would [...]

]]> By: Robert Young http://www.vcritical.com/2010/01/the-truth-about-hyper-v-memory-overcommit/#comment-9624 Robert Young Sat, 30 Jan 2010 06:08:10 +0000 http://www.vcritical.com/?p=2216#comment-9624 Oh my Hyper-V Cluster is running on Hyper-V server NOT Windows 2008 Enterprise and it does not have a console at all and had to be configured with either "CLI" commands or a remote management console........ Oh my Hyper-V Cluster is running on Hyper-V server NOT Windows 2008 Enterprise and it does not have a console at all and had to be configured with either “CLI” commands or a remote management console……..

]]> By: Robert Young http://www.vcritical.com/2010/01/the-truth-about-hyper-v-memory-overcommit/#comment-9623 Robert Young Sat, 30 Jan 2010 06:04:34 +0000 http://www.vcritical.com/?p=2216#comment-9623 Actually Both technologies scale very well and Fernando, a vmbus is provided for all hypervisor aware OS so no I/O goes through the parent partition. Again ESX, VSphere, XenServer, and Hyper-V have all good features but I do have to admit that when looking at "various workloads" on one server, ESX does handles the various memory requirements better while with Hyper-V I have to do more capacity planning. Now will MSFT come out with "Dynamic" or "Overcommit" memory, right now it does not seem to be at the top of their list yet as I stated earlier, they going with the model of capacity planning and placement first which would be to the benefit of hardware manufactures. In my environment I run over 115 server VM's on a Hyper-V Cluster w/various workloads while I run 128 on my ESX servers. I manage them both with SCVMM R2 very well but again I have to say the time I spent getting ESX up and running required a little less then the tuning I had to do with Hyper-V with NIC's, and the CSV's and I/O redirect capabilities........ Actually Both technologies scale very well and Fernando, a vmbus is provided for all hypervisor aware OS so no I/O goes through the parent partition. Again ESX, VSphere, XenServer, and Hyper-V have all good features but I do have to admit that when looking at “various workloads” on one server, ESX does handles the various memory requirements better while with Hyper-V I have to do more capacity planning.

Now will MSFT come out with “Dynamic” or “Overcommit” memory, right now it does not seem to be at the top of their list yet as I stated earlier, they going with the model of capacity planning and placement first which would be to the benefit of hardware manufactures.

In my environment I run over 115 server VM’s on a Hyper-V Cluster w/various workloads while I run 128 on my ESX servers. I manage them both with SCVMM R2 very well but again I have to say the time I spent getting ESX up and running required a little less then the tuning I had to do with Hyper-V with NIC’s, and the CSV’s and I/O redirect capabilities……..

]]> By: Fernando http://www.vcritical.com/2010/01/the-truth-about-hyper-v-memory-overcommit/#comment-9588 Fernando Mon, 25 Jan 2010 15:12:33 +0000 http://www.vcritical.com/?p=2216#comment-9588 From my understanding, the service console is a special VM, but I think it cannot completely fail without affecting the whole system. But definitely ESX VMs are less dependent on the SC. The point is that, when the VMKernel loads, it takes over, and all I/O goes directly to the Network and Storage layer, without the need of the SC. For Xen and Hyper-V, all I/O goes though the parent partition. ESXi goes further, eliminating the SC completely. From my understanding, the service console is a special VM, but I think it cannot completely fail without affecting the whole system. But definitely ESX VMs are less dependent on the SC.
The point is that, when the VMKernel loads, it takes over, and all I/O goes directly to the Network and Storage layer, without the need of the SC.
For Xen and Hyper-V, all I/O goes though the parent partition.
ESXi goes further, eliminating the SC completely.

]]> By: Phil http://www.vcritical.com/2010/01/the-truth-about-hyper-v-memory-overcommit/#comment-9587 Phil Mon, 25 Jan 2010 15:01:02 +0000 http://www.vcritical.com/?p=2216#comment-9587 Is this comment based on any experience or are you just making assumptions? On Hyper-V R1 we frequently had situations where the parent partition was totally unresponsive which seemed to relate to a problem with the Shadow Copy service when backing up. The only affect of the parent partition being unavailable was that we couldnt use the console to manage the VMs, it DID NOT cause the running VMs to fail or become unresponsive. Is this comment based on any experience or are you just making assumptions?

On Hyper-V R1 we frequently had situations where the parent partition was totally unresponsive which seemed to relate to a problem with the Shadow Copy service when backing up. The only affect of the parent partition being unavailable was that we couldnt use the console to manage the VMs, it DID NOT cause the running VMs to fail or become unresponsive.

]]> By: buy r4i http://www.vcritical.com/2010/01/the-truth-about-hyper-v-memory-overcommit/#comment-9586 buy r4i Mon, 25 Jan 2010 13:44:40 +0000 http://www.vcritical.com/?p=2216#comment-9586 Both ESX and Hyper-V are based on a hypervisor running on bare metal but uses 2 different architectures. The main difference as Andrew states is that once ESX is up and running the RHEL based servcie console can actually be unavailable and the VM’s on the ESX host will still run even though they will be unmanageable. In Hyper-V the VM’s or child partitions are dependant on both the parent partition and the hypervisor. If the parent partition is not available and working then the guest VM’s will not work at all. Both ESX and Hyper-V are based on a hypervisor running on bare metal but uses 2 different architectures. The main difference as Andrew states is that once ESX is up and running the RHEL based servcie console can actually be unavailable and the VM’s on the ESX host will still run even though they will be unmanageable.

In Hyper-V the VM’s or child partitions are dependant on both the parent partition and the hypervisor. If the parent partition is not available and working then the guest VM’s will not work at all.

]]> By: Fernando http://www.vcritical.com/2010/01/the-truth-about-hyper-v-memory-overcommit/#comment-9578 Fernando Fri, 22 Jan 2010 21:48:05 +0000 http://www.vcritical.com/?p=2216#comment-9578 More Mature is not about more stable *only*. More Mature is not about more stable *only*.

]]> By: Fernando http://www.vcritical.com/2010/01/the-truth-about-hyper-v-memory-overcommit/#comment-9577 Fernando Fri, 22 Jan 2010 21:46:31 +0000 http://www.vcritical.com/?p=2216#comment-9577 That's a point people often ignore. Normally companies will spend several thousands of dollars on servers, storage, services, etc etc On this scenario, ESX licenses prices will not be so significant. That’s a point people often ignore. Normally companies will spend several thousands of dollars on servers, storage, services, etc etc
On this scenario, ESX licenses prices will not be so significant.

]]> By: Anton Zhbankov http://www.vcritical.com/2010/01/the-truth-about-hyper-v-memory-overcommit/#comment-9571 Anton Zhbankov Fri, 22 Jan 2010 09:49:53 +0000 http://www.vcritical.com/?p=2216#comment-9571 So, is this sentence all you see in my comment? Looks like you're not going to discuss solutions, just defend Hyper-V, nothing more. So, is this sentence all you see in my comment?

Looks like you’re not going to discuss solutions, just defend Hyper-V, nothing more.

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