Skip to main content

Understanding hot-add and hot-plug in Vmware vSphere

The hot-add and hot-plug of resources are very useful feature in vSphere where you can pile in more compute resources on the fly without a downtime for machines.Few points about this feature


  • "Hot-add" refers to adding more memory to a VM whereas "Hot-plug" refers to adding a virtual CPU to a VM
  • Inorder to change the hot-add/hot-plug status of a VM , the machine should be powered off i e if the feature is disabled, you should first shutdown the machine before you can enable it. This is enabled from VM settings-> options-> advanced->memory/cpu hotplug
  • The feature is not enabled by default
  • Minimum VM hardware version of 7 is required for hot-add/hot-plug to work. If you are using a lower version of virtual hardware, first you need to upgrade it
  • Even if it hot add/plug enabled, for the hot add/plug to be effective, it should be supported by the VM guest operating system for the resources to be available to the VM
  • Hot add/plug feature is not compatible with VMware FT
  •  Feature is available only on Advanced, Enterprise and Enterprise plus versions of vSphere
  • Hot "remove" of memory and cpu is not supported by vSphere, no matter what the guest OS is



Note: Supporting OS for hot add/plug feature

  •  Windows server 2003 Enterprise (x64 and x86 ), Windows server 2008 Std, Ent and datacenter editions support memory hot add. 
  • Windows server 2003 Std x64 and Windows server 2008 Ent x64 editions support CPU hot-plug
  • Linux OS supports hot add of memory but not hot-plug of CPU

Comments

Popular posts from this blog

Windows server 2012: where is my start button??

If you have been using Windows Server OS for a while, the one thing that will strike you most when you login to a Windows server 2012 is that there is no start button!!.. What??..How am I going to manage it?? Microsoft feels that you really dont need a start button, since you can do almost everything from your server  manager or even remotely from your desktop. After all the initial configurations are done, you could also do away with the GUI and go back to server core option.(In server 2012, there is an option to add and remove GUI). So does that mean, you need to learn to live without a start button. Actually no, the start button is very much there .Lets start looking for it. Option 1: There is "charms" bar on the side of your deskop, where you will find a "start" option. You can use the "Windows +C" shortcut to pop out the charms bar Option 2: There is a hidden "start area"in  the bottom left corner of your desktop

Use Diskpart to make drives online

Issue: In disk management, disk is shown as missing or Offline in Windows Resolution: The disks can be made online by using diskpart utility - Open a command prompt->type diskpart -Inorder to list the disks in the system type: list disk -Note down the number of the disk that you want to make online -Select that disk to operate upon, For eg:, if the disk number is 1, type: Select disk 1 -Now that particular disk will be selected as teh active disk. If you type "list disk" command once more, you can see a * symbol on the left side of the selected disk -Inorder to make the selected disk online type : online disk - If the disk is made online, you will get a message that the operation is completed successfully

Kubernetes best practices in Azure: AKS name space isolation and AAD integration

Once you have decided to run your workloads in AKS service in Azure, there are certain best practices to be followed during design and implementation. In this blog we will discuss two of these recommended practices and the practical aspects of their implementation- Azure AD integration and name space isolation While AAD helps to authenticate users to your AKS cluster using the existing users and groups in your Azure AD, name space isolation provides logical isolation of resources used by them. It is useful in multi tenant scenarios where the same cluster is being used by different teams/departments to run their workloads. It is also useful in running say a dev, test and QA environment for organization in the same cluster. Combining AAD integration with name spaces allow users to login to their namespace using their Azure AD credentials AAD integration with AKS : The following Microsoft document will get you started  with AAD integration of AKS cluster.: https://docs.microsof