On VMWare Fusion, Can A VM Have Virtual Disks Stored on Two Different Hard Drives?

[danallenhtn]

I have a VM with one 600G virtual disk.  I need to add another 600G disk to this VM.  If possible, I would like the additional virtual disk to be on a different hard drive than the one where the VM is stored.  Is there a way to do that?

Thank you.

[wila · Accepted solution]

Hi,

Yes it can work.

If you need the workflow.

Settings -> Add Device -> New Hard Disk -> save as (see screenshot)

Save it to the new disk.

Beware though that by splitting up your VM over multiple physical disks and not having the virtual disks in the same bundle that your VM is more vulnerable to data corruption.

It is important to think about having good backups in a scenario like this.

For the record: Time Machine is not a good way for backing up VMs. (see also: https://kb.vmware.com/s/article/1014046​ )

--

Wil

[danallenhtn]

Why does putting the additional virtual disk on another physical drive increase vulnerability to data corruption?

[wila]

Thanks for the question. I think that statement wasn't 100% the way I should have stated it.

Splitting your VM up over multiple disks has the following side effects, some are good, some are not.

Good:

- If you need more performance then you can split a VM over multiple disks.

This used to be a recommendation for for example SQL servers where one would put read/write intensive files on a faster spindle.

Bad:

- You've increased complexity.

If you want to move a VM then you have to make sure to adjust the configuration. If you know how-to do that then you're fine, if not then you might get yourself into trouble.

Also if you make a backup then you have to backup all locations and restore accordingly.

- If one of those disks is external then it might happen that the cable gets disconnected/bad while the VM is running. Disconnecting a disk while it is running will likely cause some corruption or if you're less lucky cause the disk to become unreadable. This is not an issue if the other disk is an internal disk.

- Free storage management becomes more complex as now there's multiple places you can run out of free disk space (this also might cause permanent data loss if unlucky)

- Instead of one disk that can fail, you now have 2 disks that can fail (not a huge factor perhaps, but I've seen plenty of disks go bad over time to see it as a real issue)

--

Wil

[danallenhtn]

Another great response, I really appreciate it, thank you.

[danallenhtn]

I have a new question, I thought you might be able to get my head out of my butt on this one.  This is pretty frustrating.  It would mean a lot to me if you can help.

Linux Guest in VMWare Fusion: Tracking Down 600G disk That I Don't know How To Find