Re: [Alt-F] 2X 1.5tb JBOD upgrade

[Jeremy Laidman]

Hi

I'm not a RAID expert, but common wisdom is that JBOD, linear and RAID0 cannot lose a drive without breaking the entire volume. There might be ways to do this, known only to RAID wizards, but I wouldn't risk it, if your data has any value. The best approach would be to backup and start again, perhaps using a RAID level with redundancy, which are more amenable to changes to disks.

I believe it's possible to convert from a RAID0 into a RAID4 using an extra temporary drive for parity, then switch a data drive, then go back to RAID0. Also, it's possible to migrate from RAID0 to RAID5. But as I understand it, JBOD (JBD) is the same as "linear" which is not the same as RAID0. Can you show the output of "cat /proc/mdstat" to confirm if it's using "linear"?

Assuming linear, if you shrunk the filesystem (resize2fs?) you might be fortunate enough that all the data blocks are at the start of the volume, and only stored on the first disk. Then, you might be able to reconstruct the linear array using the new disk, with lots of luck. But I really don't like your chances, without knowing a lot more about the fundamentals of mdadm and filesystems. So I'd recommend backing up (eg to an external USB drive) and re-building.

Theoretically, you could create a non-RAID partition and filesystem on the new drive, copy the data from the RAID onto the new drive, then create a non-RAID partition and filesystem on one of the old drives, and copy the data back. At that stage, you now have 1x1.5TB and 1x2TB drives free. You can then create a linear or RAID0 volume, copy the data to it, and you're ready to go. This would probably require that you unplug the drives and plug them into a computer running Linux, with its own bootable drive, and lots of free SATA ports.

Cheers

Jeremy 

On Fri, 4 Nov 2022 at 06:20, d.i.saunders <d.i.sa...@gmail.com> wrote:

Hope there are still some people around in this forum. :)

Currently have 2 drives in JBOD setup, currently both are 1.5TB. Set as one larger disk.

I want to replace one with a 2TB Drive.

Currently all the data only adds up to 1TB. 

Is there a way to move all that data to one drive? (a)

Remove the now empty (b) drive

Add the new 2tb drive.

Join a and b giving me the new larger c 

Maybe I have not grasped JBOD.

Thanks all :)

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