Vsphere hot add cpu windows 2008

You see, there are very few in-depth studies of how Hot-Add and Hot-Plug work in different environments for some reasons. Sure, you can find a bunch of good articles about how you enable those features, why you need them, and when you may just want to leave them disabled yes, they are disabled by default. Well, I hope to fill that gap with this article.

Now, as we have clarified some non-technical things, I want to talk a bit about both technologies on the whole. These features appeared back in ESXi 4. Looks awesome! In this way, there will be no downtime if you need just to add some more power to your VMs.

You see, when Memory Hot-Add is enabled, OS pre-allocates some kernel resources to handle any possible memory changing in future. In this way, the kernel may allocate the resources to RAM that you may never use! But, no panic, all this overhead is a matter of percents.

Guest OS must support the features. Regarding all those limitations, both features are disabled by default. In order to enable them, check the appropriate checkboxes in Virtual Hardware settings. Why do I still list it here?

Just to check how vCenter behaves. I added the host to vCenter. Afterward, I checked whether the change has run smoothly with Task Manager for Windows or using top and lscpu commands Linux. Note that you need to restart Task Manager to see the changes.

In Windows Server R2, you can do that right from the window that pops up once you confirm configuration changes. Note that the NUMA nodes option is grayed out. To be honest, I did not check how adding RAM on the fly affects applications that I was running at that moment. I used the native utilities here apart from sysctl in FreeBSD. I just wanted to show how hypervisor behaves if you attempt changing VM configuration on the fly in an environment that does not support that feature.

Looks as if there were some changes applied! If you know any, please share it in comments. Here, I use lscpu to trace vCPU number change and top for identifying memory changes. Even being said to be capable of supporting Hot-Add, Ubuntu and Debian behave strange. You can follow any responses to this entry through the RSS 2. Both comments and pings are currently closed. VMware vSphere provides the hot add and hot remove virtual hardware at the hypervisor layer. Caveats at the guest OS level are the responsibility of the guest OS.

I am guessing solaris will be fine. Some linux builds will be as well if base system is compiled for it. Andy is correct — this feature requires Datacenter x64, at least that is what I recall hearing at an internal vSphere demo a couple of weeks ago.

That is, it dropped a ping or two but otherwise was ok. Still, I agree that this is one of those features where we should be the ones deciding when it is appropriate to use it. After rebooting it used both CPUs. VMotion started out as a manual process and then DRS turned it into a fully automated solution. Maybe DRS will one day be extended to use this feature to add memory or processing power on the fly if needed…. What hardware are you using for your testing?

Just wondering if it is dependent on the hardware of the ESX host. I ran more tests on the hot-add for memory. But if you simply stop the test and start it again it does start using the extra memory.

If this were an Exchange or SQL server it would probably never see the memory since it is never starting a new instance of the process, so a reboot is probably required for this too. But I think this is more useful than the hot-add CPU. My vCenter server for vSphere is a VM running on faster processors in a different virtual infrastructure. Check out Microsoft Dynamic Hardware Partitioning table for supported configurations. Note: Although Windows Server does not support hot remove, Microsoft is considering including support for hot remove in a future version of Windows Server.

Since Windows Server Enterprise Edition allows you do 4 virtual installations adding memory on the fly could be useful. I think it may be different for each application.

So basically, I think reboot is a sure thing, or restart all your applications, but some apps should let you change their affinity live. Great comments. This really takes things to a whole new level. X86 cis and will remain the architecture layout. It wold be great if you could check. You can hot add a CPU and the Windows OS will detect it, but any process that was running before the add will need to have the cpu s added to the process affinity table right click the process and click affinity.

Search for:. A few notes about the results: Memory hot remove is not supported at all by vSphere. Although virtual hardware can be hot added depending on the OS, there are caveats in certain cases A guest reboot may be required this is outlined in the table below. CPU hot unplug is supported by vSphere but was not supported by any of the Windows operating systems that I tested. Task Manager, Computer Properties, etc.