When doing an upgrade via LCM of vRA from 8.0 to 8.0.1, you might encounter this error:
Disk space on root partition (/) on VM Disk 1 (/dev/sda4) should have atleast 20 GB of free disk space.
This is because initial installation of vRA only has small disk not enough for upgrade. The issue is documented in the Known Issue for vRA 8.0.1 here
To resolve, WITHOUT POWERING OFF your Virtual Appliance, go to each of the vRA Appliance (3 if distributed) – and increse disk of Hard Disk 1 to 50GB and Hard Disk 2 to 148 GB. After which SSH to the appliance, issue the command: vracli disk-mgr resize
After a few minutes, try upgrading again.
Hope that helps