If your cluster includes ESXi 5.0 hosts, you must avoid memory overcommitment. To prevent memory overcommitment in the VSA cluster, reserve all of the memory allocated to each virtual machine that runs in the VSA cluster.

After you upgrade to vSphere 5.1 and VSA 5.1, make sure to reverse these changes to allow memory overcommitment for virtual machines.

Power off the virtual machine before configuring the memory settings.


In the vSphere Web Client, right-click a virtual machine and select Edit Settings.


Click the Virtual Hardware tab and click Memory to expand the menu.


In the Reservations field, set appropriate memory reservations.

To avoid memory overcommitment for VSA 5.0, enable memory reservation by selecting the Reserve all guest memory (All locked) check box.

To allow memory overcommitment for VSA 5.1, disable memory reservation by deselecting the Reserve all guest memory (All locked) check box.


Click OK.

Repeat the same steps for all virtual machines that run in the VSA cluster.