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VSICM51 - Slide 12-23 - Removing a Host from the DRS Cluster



1. Wrong:

The last sentence in the first paragraph in slide notes states:

Right-click the host and select Remove.
1. Correct:

This sentence is out of the context: if you right-click a host and select Remove, you remove it from the vCenter Server, not the cluster. To remove a host from a cluster, instead, you need to:

  • Right-click the host in the inventory and select Enter Maintenance Mode.
  • When the host is in maintenance mode, drag it to a different inventory location, either the top-level datacenter or to a different cluster.
1. Source:

vSphere 5.1 Documentation Center.



2. Wrong:

The second bullet in slide notes state:

Because a host must be in maintenance mode before you can remove it, virtual machines with disks on local storage must be powered off or migrated to shared storage with vMotion. Virtual machines on shared storage will be migrated.
2. Correct:

vMotion migrates only the virtual machines execution context from one host to another; it is instead Storage vMotion that migrates virtual machines files to a shared storage.

2. Info:

The above quoted sentence is rather confused and should be revised as it might give students a wrong idea about the process. Basically, to remove a host from a cluster, you need put it into maintenance mode. In order to do so, all of its virtual machines must be either shutdown, suspended or evacuated.

  • Shutting down or suspending all virtual machines in the host will be enough to let it enter the maintenance mode, regardless where virtual machines files are located.
  • If virtual machines are instead to be evacuated whilst they're still up and running, then:
    • If virtual machines are stored on a shared storage, they can be evacuated from the host either manually with vMotion or automatically by DRS, if set to "Fully automated" automation level.
    • If virtual machines are stored on a local storage, they have to be - first of all - manually migrated to a shared storage using Storage vMotion, then evacuated from the host either manually with vMotion or automatically by DRS, if set to "Fully automated" automation level. Alternatively, Enhanced vMotion - introduced in vSphere 5.1 - can be leveraged to combine vMotion and Storage vMotion into a single operation to manually evacuate all virtual machines.

Last modified onThursday, 12 December 2013 18:10
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