I kept getting disk full issues when upgrading esx, this is such a silly error, and I really had no way around it outside of loading esx from a full iso and ilo in to boot. But I found a somewhat easier way to do it now via SSH and the upgrade update file.
- download the zip file from: https://my.vmware.com/group/vmware/patch#search
- upload it to a datastore
- Renamed it to update.zip – not required, but makes it easier
- esxcli software vib update -d /vmfs/volumes//update.zip
- reboot
- If complete, go ahead and delete the file if you want to reclaim the space.