You can upgrade an ESXi 5.0.x or update an ESXi 5.1 host directly to ESXi 5.1.x, and in most cases, you can migrate an ESX 4.x or upgrade an ESXi 4.x host directly to ESXi 5.1.x.

The details and level of support for an upgrade, migration, or update to ESXi 5.1 from version 4.x ESX and ESXi hosts, and version 5.0.x and 5.1 ESXi hosts, depend on the host to be upgraded and the upgrade method that you use.

The following ESX/ESXi 4.x, ESXi 5.0.x and ESXi 5.1 versions are supported for upgrade, migration, or update to ESXi version 5.1.x.

ESX/ESXi 4.0.x (including all released updates and patches)

ESX/ESXi 4.1.x (including all released updates and patches)

ESXi 5.0.x (including all released updates and patches)

ESXi 5.1

Supported Scenarios for Upgrade, Migration, or Update to ESXi 5.1.x

Scenario for Upgrade, Migration, or Update to ESXi 5.1.x

Support

3.x ESX and ESXi hosts

Not supported for direct upgrade.

You must upgrade version 3.x ESX and ESXi hosts to ESX or ESXi version 4.x before you can upgrade them to ESXi 5.1.x. See the vSphere 4.x upgrade documentation.

Alternatively, you might find it simpler and more cost effective to do a fresh installation of ESXi 5.1.x.

4.x ESX host that was upgraded from ESX 3.x with a partition layout incompatible with ESXi 5.x

Not supported.

The VMFS partition cannot be preserved. Upgrading or migration is possible only if there is at most one VMFS partition on the disk that is being upgraded and the VMFS partition must start after sector 1843200. Perform a fresh installation. To keep virtual machines, migrate them to a different system.

4.x ESX or ESXi host, migration or upgrade with vSphere Update Manager

Supported. See Using vSphere Update Manager to Perform Orchestrated Host Upgrades and the Installing and Administering VMware vSphere Update Manager documentation.

4.x ESX or ESXi host, interactive migration or upgrade

Supported. See Upgrade or Migrate Hosts Interactively.

The installer wizard offers the choice to upgrade or perform a fresh installation. If you upgrade, ESX partitions and configuration files are converted to be compatible with ESXi.

4.x ESX or ESXi host, scripted upgrade

Supported. See Installing, Upgrading, or Migrating Hosts Using a Script.

In the upgrade script, specify the particular disk to upgrade on the system. If the system cannot be upgraded correctly because the partition table is incompatible, the installer displays a warning and does not proceed. In this case, perform a fresh installation. Upgrading or migration is possible only if there is at most one VMFS partition on the disk that is being upgraded and the VMFS partition must start after sector 1843200.

4.x ESX host on a SAN or SSD

Partially supported.

You can upgrade the host as you would a normal ESX 4.x host, but no provisions will be made to optimize the partitions on the disk. To optimize the partition scheme on the host, perform a fresh installation.

4.x ESX host, missing Service Console .vmdk file, interactive migration from CD or DVD, scripted migration, or migration with vSphere Update Manager

Not supported.

The most likely reasons for a missing Service Console are that the Service Console is corrupted or that the VMFS volume is not available, which can occur if the VMFS was installed on a SAN and the LUN is not accessible. In this case, on the disk selection screen of the installer wizard, if you select a disk that has an existing ESX 4.x installation, the wizard prompts you to perform a clean installation.

4.x ESX or ESXi host, asynchronously released driver or other third-party customizations, interactive migration from CD or DVD, scripted migration, or migration with vSphere Update Manager

Supported with ESXi Image Builder CLI.

If a 4.x host contains customizations, such as third-party VIBS or drivers, upgrading with the standard VMware installer ISO will result in the loss of those customizations, and possibly an unstable system. See Upgrading Hosts That Have Third-Party Custom VIBs. You can ESXi Image Builder CLI to create a customized ESXi installer ISO file that includes the VIBs or drivers. See the information on Image Builder in the vSphere Installation and Setup documentation.

5.0.x or 5.1 ESXi host, asynchronously released driver or other third-party customizations, interactive upgrade from CD or DVD, scripted upgrade, or upgrade with vSphere Update Manager

Supported.

When you upgrade an ESXi 5.0.x host or 5.1 host that has custom VIBs to version 5.1.x, the custom VIBs are migrated. See Upgrading Hosts That Have Third-Party Custom VIBs.

5.0.x ESXi host

Methods supported for direct upgrade to ESXi 5.1.x are:

vSphere Update Manager.

Interactive upgrade from CD, DVD, or USB drive.

Scripted upgrade.

Auto Deploy. If the ESXi 5.0.x host was deployed using Auto Deploy, you can use Auto Deploy to reprovision the host with an ESXi 5.1.x image.

esxcli, for upgrades to ESXi 5.1 Update 2 and later. esxcli is not supported for upgrades to ESXi 5.1.0 or 5.1 Update 1.

5.1 ESXi host

Methods supported for direct update to ESXi 5.1.x are:

vSphere Update Manager.

Interactive update from CD, DVD, or USB drive.

Scripted update

Auto Deploy. If the ESXi 5.1 host was deployed using Auto Deploy, you can use Auto Deploy to reprovision the host with an ESXi 5.1.x image.

esxcli .