User guide

Applying Extended Functionality 114
The Distributed Power Manager (DPM) application will help maximize data center electrical power
efficiency by checking DRS for physical server utilization then using vMotion, will move Virtual
machines to servers in order to fully unload servers than idle them or power them down for maximum
power savings.
Dell uses the same vMotion capability when a UPS is in a critical power situation to move virtual
machines off of a server that has a critical power situation. Dell MUMC will now write alarms/alerts into
vCenter, which, in turn, will trigger vMotion.
VMware uses the term “setting a server into Maintenance mode” to trigger the vMotion. It is called this
because before performing maintenance on server, the data center manager needs to clear the Virtual
Machines from the server.
Understanding Maintenance Mode
Both standalone hosts, and hosts within a cluster, support the maintenance mode. Only VMware
ESX/ESXi Server 3.0 and later supports maintenance mode for standalone hosts.
A host enters or leaves maintenance mode only as the result of a user request. If the host is in a cluster
when it enters maintenance mode, the user is given the option to evacuate powered-off virtual machines.
If this option is selected, each powered-off virtual machine is migrated to another host, unless there is no
compatible host available for the virtual machine in the cluster. While in maintenance mode, the host
does not allow deployment or “power-on” of a virtual machine. Virtual machines that are running on a
host entering maintenance mode need to be either migrated to another host or shut down (either
manually or automatically by DRS).
When no more running virtual machines are on the host, the host's icon changes to include 'under
maintenance' designation and the host's Summary panel indicates the new state. The default
automation mode of a virtual machine determines its behavior when the host (in a DRS cluster) it is
running on enters maintenance mode:
Any fully automated virtual machine is migrated automatically.
For a partially automated or manual virtual machine, a recommendation for further user action is
generated and displayed.
Configuring Maintenance Mode Behavior in vCenter
To configure the maintenance mode feature behavior, we provide here a simple configuration example:
Enable the DRS in “Fully Automated” automation level with following steps:
1
Open the vCenter server in a vSphere client.
2 Right-click and select Cluster > Edit Setting > Turn on VMware DRS . Click on next with all default
values.
NOTE: With this example, you choose to move all the virtual machines from this server to another server of the same
cluster. You can also define other behaviors according to your needs
0119_2-Dell MUMC UG.book Page 114 Saturday, November 2, 2013 4:59 PM