This section describes the tasks involved to upgrade your appliances.

Once you are ready (and if there is no HA configuration for the Core), start by upgrading the Edge appliances first. After these appliances are successfully upgraded, proceed to upgrade the Cores.

If you have Core deployed in an HA deployment, upgrade the Cores first, followed by the Edge appliances.

Edge software and functionality is incorporated into the Edge appliance software image. When performing the upgrade there is a reboot of the appliance, which causes an interruption or degradation of service both to Edge and WAN optimization (if there is no HA).

In the case of Edge HA deployments, upgrade one of the Edge peers first, leaving the other Edge in a normal operating state. During the upgrade process the surviving Edge enters a degraded state. This state is expected behavior. After the upgrade of the first Edge in the HA configuration is complete, check that the two Edge HA peers rediscover each other before proceeding with the upgrade of the second Edge.

Before upgrading the Core, ensure that any data written by Edge to LUNs projected by the Core is synchronized to the LUNs in the data center storage array. In addition, take a snapshot of any LUNs prior to the upgrade.

If a Core is part of an HA configuration with a second Core, then you must upgrade both before the Edges that the Cores are responsible for are also upgraded. You can choose which Core you begin with because the HA configuration is active-active. In either case, the upgrade triggers a failover when the first Core is rebooted with the new software version, followed by a failback after the reboot is complete.

The same process occurs with the second Core. Therefore, during the Core HA upgrade there are two separate instances of failover followed by failback. Whichever Core is upgraded first, continue to upgrade the second Core of the HA pair before upgrading the Edges.

When upgrading a Core that is not part of an HA configuration, there is an interruption to service for the projected LUNs to the Edges. You do not need to disconnect the Edge appliances from the Core, nor do you need to unmap any required LUNs managed by the Core from the storage array.

When upgrading a Core that is part of an HA configuration, the peer Core appliance triggers an HA failover event. This failover is expected behavior. After the upgrade of the first Core is complete, check to ensure that the two Core HA peers have rediscovered each other and that both are in ActiveSelf state before upgrading the second Core.