Upgrading RAID Volume Size

That is kind of how a Drobo should work. It has controlled hardware, so can do that kind of thing.

With SoftRAID and any actual RAID, all partitions are the same size. So replacing one disk will not help. You would need to replace all 4 disks. then SoftRAID can resize the volume*.

* there is currently a bug in SoftRAID, which we are trying to fix for 7.1, that does not allow resizing volumes. You would need to use SoftRAID 6.0.5, in Big Sur or older, to perform the volume resizing, then connect it back to this system. Resizing also only supports HFS at this time, which we hope to also fix in 7.1

It's not a Drobo.  

So all drives need replacing, even with fixes?  That means I need a drive that can hold everything, transfer them for safekeeping, then re-stripe, then bring back the files?

Cheers

@dabee 

On our end we intend to fix the volume resize issue in 7.1 in a couple months. then you can "resize" the volume, once all disks are replaced, yes.

I'm confused.  If all disks are replaced, what needs to be resized?  It's a brand new setup.  There's no way of "not moving all files off the current RAID", am I right?

@dabee 

What I am describing is a scenario like this:

You have 4 4TB drives. A 12 TB RAID 5 volume.

You want more space. If you replace one drive with an 8TB, your volume will still be 12TB. It cannot be resized. When you replace all 4 disks with 8TB drives, the volume will still be 12TB. However, now it can be resized to 24TB.

If you do not need to keep the files on teh volume (it is backed up), then you can just pull out the 4TB drives, put in new 8TB drives, and create a 24TB volume, then copy the data to it.

What you cannot do is replace one drive (4-4-4-8) and expect a volume larger than 12TB. All partitions on a RAID volume are the same size, in RAID. Drobo is not really RAID, it is something else. and from what I have seen and heard, higher reliability issues because of this way of approaching volumes.

I'm looking for a minimal route to more volume.  How can I increase my OWC RAID to more than my current 12 TB (4 x 4 TB drives) setup.  Can I replace them individually, one per night, then re-sized on the 5th night?

@dabee 

That is what I described. With the cavaets:

This has to be an HFS volume.

To perform the resize, you need to connect to a Big Sur or older computer, so you can resize with 6.0.5l; or wait until 7.1 is released when we are adding support for resizing both APFS and HFS volumes.

OK, you keep on focussing on versions.  Let's get past that and assume version 7.1.  I won't need to pull the files then?  Again, replacing one and letting it catch up, until all 4 drives are completed, before a rebuild?  This sounds very sketchy.  

@dabee 

Its not sketchy, that is essentially 4 rebuilds.

Then a resize.

Is there documentation published somewhere?  I'm not doubting it's essential.  It's sketchy because I seriously cannot mess this up, and I'm not getting any clear procedure how to do this.  

@dabee 

The steps are:

get your 4 new disks. I recommend you certify each of them (you can do all at once, as it takes several days to certify a disk), as disks are sold untested, so certify helps ensure you were not sent defective drives

"remove disk"

Pull out that disk and insert the new disk.

"Initialize disk"

"Add disk"

let it rebuild. Make sure volume optimization is set to workstation, or server, so it rebuilds faster.

when completed, repeat with next disk, until all 4 disks are replaced.

That is stage 1. When you get that far, you can post and I can see if there may even be a beta version for expanding the volume to full size.

1. OK, remove disk is the logical volume.  So the whole RAID is now removed from SoftRAID.  
2. Pull out Disk 1, replace with brand new larger disk.  
3. Initialize disk
4. Add disk (optimize for workstation)

At this point, I have the following:

• New Disk 1 (8 TB empty?)
• Disk 2 (4 TB original)
• Disk 3 (4 TB original)
• Disk 4 (4 TB original)

The rebuild...brings back the full Volume?

BTW I'm not doing this now.  I'm just researching how it's done in the future.  I'm not concerned with versions. This will be accomplished 7.1 or later.  

@dabee 

This is RAID 5, correct? then your volume is mounted at all times. When you are done rebuilding, then it is the same as the other 3. (except there is free space at the end of the disk)

Yes it is RAID 5.  OK, this sounds relatively painless, outside of the single drive replacements.  

BTW this should be published in a clear document online.  It would be seriously helpful.