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Upgrade considerations

Before you upgrade multiple storage arrays, review the key considerations as part of your planning.

Current versions​

You can view the current ThinkSystem SAN OS software versions from the Manage page of the DE Plugin for vCenter for each discovered storage array. The version is shown in the ThinkSystem SAN OS Software column. The controller firmware and NVSRAM information is available in a pop-up dialog box when you click on the OS version in each row.

Other components requiring upgrade​

As part of the upgrade process, you might also need to upgrade the host's multipath/failover driver or the HBA driver so that the host can interact with the controllers correctly.

Dual controllers​

If a storage array contains two controllers and you have a multipath driver installed, the storage array can continue to process I/O while the upgrade occurs. During the upgrade, the following process occurs:

  1. Controller A fails over all its LUNs to controller B.
  2. Upgrade occurs on controller A.
  3. Controller A takes back its LUNs and all of controller B's LUNs.
  4. Upgrade occurs on controller B.

After the upgrade completes, you might need to manually redistribute volumes between the controllers to ensure volumes return to the correct owning controller.