I decided to try out unRAID not for any of its storage features but as a lazy way to do KVM virtualisation with device passthrough. Because my system only contains a single SSD, and unRAID was whinging that the "Array must be started to view virtual machines", after reading that it wouldn't touch a foreign disk unless you agreed to format it (with warning of data loss), I decided to assign my SSD as part of the "array" and start the "array".

 

Now that didn't get me any further and I still couldn't view VMs, I tried to mess around a bit creating some folders that unRAID wanted to be present on the USB drive, but still no go. So after deciding that this was a fruitless exercise and I should probably look into setting up a different Linux distro on a USB drive to mess around with KVM, I decided to reboot back into my main OS.

 

But lo and behold, unRAID had without warning shat on my SSD's partition table and turned it into one big unrecognised partition. Thanks unRAID! In the end I slapped a Debian Live image on the same USB drive and ran parted on an old laptop to figure out what the original partition layout was, and recreated it on this system.

(For those in the same position, for a legacy-boot Windows 7 with a "System Reserved" partition, it's one NTFS partition at 1049KB offset, 105MB large, and at 106MB offset, another NTFS partition that is the size of the rest of the disk. Unset lba for both partitions and set boot for partition 1.)

 

So while it was a relatively straightforward fix for me, and no actual data was lost, it can be quite upsetting for less technical folks and aside from any of that it's just plain bad practice for software to just wipe a partition table without warning.

 

Thanks for reading and I hope you fix this bug (or if you don't want to call it a bug, "careless behaviour").

While I agree that the behaviour is not ideal, I do have to wonder about the wisdom of assigning a disk to an array and expecting it to not be touched. It's assumed that when you start assigning disks to the array, you intend to use them in the array. Assigning disks to a foreign OS with data you care about from a different OS isn't the best move.

 

If you would rather learn by doing instead of reading up and watching videos, I get it. Just don't expect to have all those lessons come easy.

It's ironic that someone as "technical" as you would think assigning a drive to any sort of storage array would result in the drive structure being untouched.

 

"I know all about it, I've been working with computers for 20 years" said by many people who bring me their ruined computers to be fixed after they did something stupid and basic... 

Edited August 24, 20178 yr by HellDiverUK

Come on, don't be silly. RAID controllers have for centuries allowed you to assign passthrough disks, which would then stay untouched. Don't make me regret even posting here; I won't be using unRAID in the future anyway, I just wanted to leave this bug report in case someone else encounters the same issue and it causes a bigger problem for them than it has for me. If you don't have anything meaningful to add, don't reply.

1 hour ago, Muf said:

RAID controllers

This is UNraid. Not RAID at all.

1 hour ago, Muf said:

I just wanted to leave this bug report in case someone else encounters the same issue

It's been this way since the software came out MANY years ago, and it's been discussed before. It really doesn't seem to be an issue for 99.9% of people.

1 hour ago, Muf said:

Don't make me regret even posting here; I won't be using unRAID in the future anyway

We really are a friendly bunch when you don't come in with an attitude.

 

If your original post would have been a simple question,

"I want to try unraid as a KVM manager, what do I need to do to make that work, since all the guides assume I want to set up an array?"

You would have gotten friendly responses on how to accomplish that. Nobody would have given you attitude, and you would have gotten the info you needed. Instead this happened.

 

1 hour ago, Muf said:

If you don't have anything meaningful to add, don't reply.

This may not be meaningful to you, since you seem to have all the answers already. Perhaps the attitudes you encounter are a reflection of the attitude you bring to the table.

FYI, unRAID does have that type of pass-through capability via the unAssigned Devices plugin.  It wouldn't have solved your situation completely, though - unRAID requires at least one device assigned to the array before starting the array (an "assigned" device rather than an "unassigned" device).  Next time ask first?