Hi,
Yes this is possible, but it has a few caveats.
Your 2 hosts should be from somewhat the same time frame. Eg. if you bought the two hosts around the same time then I don't expect a lot of trouble.
If OTOH one host is from 2018 and the other one is from 2009 then I do expect some trouble. The reason is that the CPUs in the latter case are very different and if your VM is running windows then you might bump into activation issues due to the CPU changing too often.
There are a number of things to keep in mind:
- Always shut down the VM on host 1 before you use it on host 2.
- Do not keep snapshots open, do not use auto protect
- Your VM is extra fragile when it lives on an external disk. Having a cable disconnect when it is running has a fairly high chance of corrupting your VM.
- Make backups often, manually or automated (see below)
- Exclude the VMs from Time Machine (TM should never be used for virtual machine backups, see also VMware Knowledge Base )
- Guest OS licensing, especially if you keep 2 copies of each VM it might count as 2 licenses.
- For the file system on an external disk preferably use HFS+ or APFS, do not use ExFAT. ExFAT has a number of problems, both in reliability as well as performance. If you have to share with a host running Windows or Linux then FAT32 would still be preferred. Note however then you then should look into using split file disks and that your virtual disk(s) should not be over 128GB in size due to the 4GB disk slice limit.
Scenario 1:
If this is something you need to do on a regular bases then it is probably a good idea to have the VM(s) live on an external disk.
This would match best with a VM that constantly moves between host 1 and host 2.
Scenario 2:
Keep your VM on your host and only use the external disk to move the VM on need.
This works when you only need to use the VM on another host every now and then.
Scenario 3:
Keep a copy of both VMs on each host and share your data via cloud services such as dropbox, google drive, windows onedrive etc..
Backups can be made manually with the VM shut down and making a complete copy of the VM bundle to an external disk (not the same disk as that your VM lives on!)
If you want to automate that you can use the product I wrote for making backups of VMs (Vimalin), see my signature for more details on that.
Note that for scenario 2) Vimalin can also help by restoring a VM that was backed up to another host.
Hope this helps,
--
Wil
