ESX 3i Update Service Client

Reverting to a Backup ESX Server HW Host Configuration

Each ESX Server HW host has two banks, Bank 1 and Bank 2, with one bank in active mode and the other in standby mode. The active bank is the one from which the system is booted.

When you update the ESX Server HW host, the VMware update service writes the newly downloaded update file to the standby bank. If the download is successful, the host is rebooted. On reboot, the newly updated bank becomes the active bank. If the update is successful, the host continues to boot from the new active bank until the next update. Upon the next update, the update service updates the standby bank, and the standby bank becomes the new active bank.

For example, suppose the current active bank is Bank 1. When you update the host firmware, the update process places the new build on Bank 2 and makes Bank 2 the active bank. If the update is successful, you continue to boot from Bank 2 until the next update. At that point, the update process places the new build on Bank 1 and makes Bank 1 the active bank.

If an update fails and the ESX Server HW host is not able to boot from the new bank, the host reverts to booting from the original bank the next time you reboot.

During the boot process, you can manually select the standby bank to boot into the previous build. This causes a rollback. In other words, when you manually select the standby bank, the standby bank becomes the new active bank and remains the active bank until you perform another update or manually select the other bank.