Required connections for using uninterruptible power supplies with standard or mirrored HA pairs

You can use a UPS (uninterruptible power supply) with your HA pair. The UPS enables the system to fail over gracefully if power fails for one of the nodes, or to shut down gracefully if power fails for both nodes. You must ensure that the correct equipment is connected to the UPS.

To gain the full benefit of the UPS, you must ensure that all the required equipment is connected to the UPS. The equipment that needs to be connected depends on whether your configuration is a standard or a mirrored HA pair.

For a standard HA pair, you must connect the controller, disks, and any FC switches in use.

For a mirrored HA pair, you must connect the controller and any FC switches to the UPS, as for a standard HA pair. However, if the two sets of disk shelves have separate power sources, you do not have to connect the disks to the UPS. If power is interrupted to the local controller and disks, the controller can access the remote disks until it shuts down gracefully or the power supply is restored. In this case, if power is interrupted to both sets of disks at the same time, the HA pair cannot shut down gracefully.