Detach old ESXi installation devices

By | March 22, 2018

When clearing up host storage, you might sometimes encounter an error when you come to detach a device. The cause of this can be an old ESXi installation and you’ll need to erase the ESXi partitions in order to detach old ESXi installation devices.

The typical use case for this is reclaiming SAN boot LUNs that are no longer required since we’ve moved to SD card / Local disk / AutoDeploy. Reclaiming unused storage is always a good idea 😉

The first step in the process is unmounting any datastores that exist on the device:

When Unmount is selected, we’ll need to confirm the hosts to unmount from:

The UI should update to show that it is now unmounted.

If this was a normal device we would then detach it – let’s do this now.

Aha, we get an error message:

This means that an ESXi install has been found on the device, even if it is old and inactive. In order to get past this, we will make sure this isn’t an active installation and then we will erase the partitions on the device.

A summary of the partitions is displayed and confirmation of erasure is required:

The device can be successfully detached now that the ESXi installation has been erased.

That’s it 🙂 I’m sure there is a way to automate this, but I only had a few to do so I took the lazy way out this time !