My Unraid server is down, I need some new parts etc. Meanwhile I have my old pc which runs Linux.

 

What I'd like to do is format a hdd in xfs, add it to my Linux pc as a data disk, and then later on use it in Unraid, without losing the data or needing to reformat.

 

Is this possible? from what I've read, Unraid uses a special disk format layout, but I'm hoping there are some utils etc that can help? the files can then be moved into the same folder layout with share names as in Unraid.

Edited September 24, 20241 yr by MrCrispy

Why not boot from your Unraid key, and format the drive there using Unassigned Devices? As long as you don't mess with array assignments or accidentally format your Linux boot disk it should work fine.

 

I'd make a backup of the config folder on the key before doing this, just in case, plus it never hurts to have a current backup of your config.

24 minutes ago, JonathanM said:

Why not boot from your Unraid key, and format the drive there using Unassigned Devices? As long as you don't mess with array assignments or accidentally format your Linux boot disk it should work fine.

 

I'd make a backup of the config folder on the key before doing this, just in case, plus it never hurts to have a current backup of your config.

so if I boot from Unraid key,, attach the new hdd, format in Unraid, will the disk then be usable in a normal Linux distro? the booting from Unraid key will only be a temp step. I can then use it Linux, fill it with data and Unraid will later see it?

14 minutes ago, MrCrispy said:

so if I boot from Unraid key,, attach the new hdd, format in Unraid, will the disk then be usable in a normal Linux distro? the booting from Unraid key will only be a temp step. I can then use it Linux, fill it with data and Unraid will later see it?

Yep.

1 hour ago, JonathanM said:

Yep.

How? Does Unraid use the same disk layout as Linux? If not how are they compatible?

Unraid uses standard linux, but it's a little more specific. So a disk formatted in linux CAN be made compatible with Unraid, but a disk formatted in Unraid should be readable in linux by default.

34 minutes ago, JonathanM said:

So a disk formatted in linux CAN be made compatible with Unraid

Interesting. Can you give more details on this (if its not proprietary) ? I'm trying to find where I read about Unraid's disk layout being different, but Google is so much worse now and I can't.

 

Actually now that I think about it, one of the benefits of Unraid has always been that data is in native format, so in the event of a crash its readable in other pc's (unlike striped raid etc), which would imply that a Unraid formatted disk is readable in Linux. I just wasn't sure it would be writeable, support other disk operations on the file system - but you are saying it does, right?

52 minutes ago, MrCrispy said:

Can you give more details on this

I don't know the exact details, but some of the major things are a single partition starting at a specific offset, I think 64 or 2048, something like that.

54 minutes ago, MrCrispy said:

I just wasn't sure it would be writeable, support other disk operations on the file system - but you are saying it does, right?

Yep. It's a standard linux layout, just more particular to accommodate the parity system.

 

Thank you!

@JonathanMI have a request for Unraid devs/team please. I am unable to boot from an Unraid USB on this PC - I made another thread here - https://forums.unraid.net/topic/176032-pc-wont-boot-from-unraid-usb. I went ahead and installed a fresh Linux distro on my PC. the HDD is untouched for now. 

 

My plan was to boot up and install a trial Unraid, then use it format the HDD in xfs compatible with Unraid, and then use it in Linux. Since I cannot do this. is there any cmd line tool you can give me that will let me format the disk in an Unraid compatible XFS? or perhaps this can be done with standard Linux tools?

 

thank you