In vSphere, you can persistently map a device (bus address) to a device name (alias). You can modify the mapping by using the Device Alias Configuration host profile. Using persistent mapping can help avoid compliance warnings for stateless hosts, and is also useful for stateful hosts.

The Device Alias Configuration host profile is selected by default, which means that aliases are assigned to each device. For example, if a host does not recognize one of the NICs during the boot process, the NIC aliases no longer change. That can help for management with scripts, and if you apply a host profile from a reference host.

Note: To avoid errors, do not disable or edit the Device Alias Configuration host profile.

To ensure uniform, persistent, and stable device naming across all hosts, use the device alias profile with homogeneous hosts only. Homogeneous hosts are hosts that are identically configured with the same network and storage cards in the PCI bus.

Note: Always update the BIOS up to the latest version. For systems with earlier versions of the BIOS, the BIOS might not provide accurate location information for on-board devices.

Device Alias Configuration Compliance Failures

If you apply the host profile from a reference host to hosts that are not fully homogenous, a compliance check might result in a compliance failure. Such hosts are, for example, hosts that contain different PCI cards or have different BIOS versions. The compliance check ignores extra devices on the host that were not on the reference host. Select the host with the fewest devices as the reference host.

If the compliance check shows that the hosts are not fully homogeneous, the compliance failure cannot be remediated without modifying the hardware itself.

If the compliance check shows that the device aliases, for example, names such as vmhba3, are different from those on the reference host, remediation might be possible.

  • To remediate a host that is not provisioned with vSphere Auto Deploy, perform host profile remediation and reboot the host.
  • To remediate a host that is provisioned with vSphere Auto Deploy, reprovision a host.

Upgrading Systems for Device Alias Profiles

Consider the following problems when you upgrade from previous versions of ESXi to a current version:

  • For installed hosts, that are not provisioned with vSphere Auto Deploy, upgrading the ESXi hosts preserves aliases. After they are upgraded, aliases remain stable if the BIOS provides the information.
  • When you upgrade a cluster of ESXi hosts provisioned with a vSphere Auto Deploy image, the aliases do not change because ESXi uses the same algorithm to generate aliases as earlier versions. Generate a new host profile for the reference host. This host profile includes the Device Alias Configuration profile. Set up vSphere Auto Deploy to apply the reference host's host profile to all other hosts for consistent device naming across your cluster.

For information about how the ESXi host determines the order in which it assigns names to devices and how to change the names assigned by the ESXi host, see Knowledge Base article KB 2091560.