SteelFusion Appliance Upgrade

This chapter provides some general guidance when upgrading your SteelFusion appliances. It includes the following topics:

Before you perform a software upgrade to a SteelFusion deployment, there are a few steps to consider. This section describes best practices that you can incorporate into your own upgrade and change control procedures.

For detailed instructions and guidance on upgrading each of the products, see the SteelFusion Edge Installation and Configuration Guide and the SteelFusion Core Installation and Configuration Guide.

Prior to upgrading, complete the following prerequisites:

• Alert users - Depending on your deployment you might have a full-HA SteelFusion configuration at the data center and at the branch office. This configuration allows you to perform software upgrades with minimal or zero disruption to your production environment. Whether this is your case or not, you should schedule either downtime or an at risk period so that your users are aware of any possible interruption to service.

• Alert IT staff - Because you might also be using your Edge appliances simultaneously for WAN optimization services, you should alert other IT departments within your organization: for example, networking, monitoring, applications, and so on.

• Software - Gather all the relevant software images from the Riverbed Support site and consider using the SCC to store the images and assist with the upgrade.

When downloading the software images, make sure to download the release notes so that you are aware of any warnings, special instructions, or known problems that can affect your upgrade plans.

• Configuration data - Ensure all your Cores and Edges have their current running configurations saved to a suitable location external to the appliances themselves. You can use the SCC to assist with this task with the Core.

If you are planning to upgrade both Core and Edge as part of the same procedure, then the normal sequence—in which there is no HA configuration at the Core—is to upgrade the Edge appliances and then upgrade the Cores.

If there is HA at the Edge and no HA at the Core, the sequence is the same—Edge first followed by Core with standby Edges preceding active Edge upgrades.

However, if there is HA at the Core, regardless of whether or not there is HA in the branch office with Edges, upgrade the Core first, followed by the Edge.

The following table summarizes the sequence.

Deployment	Upgrade phases
Deployment	First	Second
Core - Edge	All Edges owned by the Core	Core
Core HA - Edge	Core HA	All Edges owned by the Core HA
Core - Edge HA	All Edges are owned by the Core. Upgrade the standby Edge first, and wait for it to be synchronized with the active Edge. Next, upgrade the active Edge.	Core
Core HA - Edge HA	Core HA	All Edges are owned by the Core HA. Upgrade standby Edges before upgrading active Edges.

If you have an HA deployment, it is possible you can have mixed software versions between HA peers for a short period of time. You can also run with mismatched software versions between Core and Edge for short periods of time; however, we do not recommend this practice.

In SteelFusion 4.2 or later of Core and Edge software, there are restrictions in place to enforce supported upgrade and downgrade paths. You can upgrade or downgrade the Core or Edge software up to a maximum of two versions beyond the current version.

If you attempt to upgrade or downgrade to an unsupported version, a warning opens and the upgrade or downgrade does not proceed.

If there are any doubts about any of these procedures, contact Riverbed Support.

Although it is expected that the upgrade procedure will progress and complete without any problems, you should have a contingency plan to back out or restore the previous state of operations.

Both Core and Edge upgrade procedures automatically install the new software image into a backup partition on the appliance. The existing (running) software image is in a separate (active) partition. During the reboot, which is part of the upgrade procedure, the roles of the backup and active partitions are reversed. This action ensures that if you require a downgrade to restore the previous software version, a partition swap and reboot are all that should be required.

If you have a lab or development environment in which some nonproduction SteelFusion appliances are in use, consider doing a trial upgrade. This upgrade ensures you have some exposure to the upgrade processes, enables you to measure the time taken to perform the tasks, and gain other useful experience. You can complete the trial upgrade well ahead of the production upgrade to confirm the new version of software operates as expected.

This section describes the tasks involved to upgrade your SteelFusion appliances. It contains the following sections:

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 SteelFusion 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).

While you do not need to disconnect the Edge from the Core, you should stop all read and write operations for any VSP-hosted services and any external application servers that are using the Edge for storage connectivity. Preferably, shut down the servers, and in the case of VSP, place the ESXi instance into maintenance mode.

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.