Physical Disk Reorder Question

Hi all.

I was wondering if physical drive order matters. Imagine I had a case with 5 SATA ports:

1: 1TB
2: 1TB
3: 4TB
4: 4TB
5: (empty)

If I were to reorder the drives as:

1: (empty)
2: 1TB
3: 4TB
4: 4TB
5: 1TB

Will that break my raid array? I ask, because my case has more SATA ports that internal hard drive slots. All internal hard drive slots are currently full, and I want to start replacing my smaller drives with larger drives. So my first thought was to:

Step 1: plug in a drive into sata port 5 (and leave lose at the bottom of my case)
Step 2: do a btrfs replace command for the drive in sata port 1 with sata port 5.
Step 3: physically remove the drive connected to sata port 1, and physical move the drive from sata port 5 to sata port 1.

Will my RAID 10 array still load? Or because I changed the drive order, will it not recognize things and break?

@kupan787 Hello and a belated welcome to the Rockstor community to you.

Re-arranging drives shouldn’t break a pool, as long as drive-controller compatibility exists of course. Btrfs itself tracks drives by their btrfs uuid so as long as it can read the drives it should be able to re-assemble the pools on those drives. Rockstor, as it has to track drives that may well not have a format of any kind, uses hardware serial numbers, so again, as long as the drive can be read your should be good. But don’t do any live unplugging plugging, do all re-arrangements with the system powered off. Then once all the drives have been re-arranged wire / port / controller wise, power up again and hope for the best :slight_smile:. As always; best to make sure this is not your only copy of the date, as there could still be a cable/ connection / compatibility issue encountered that would put your data at risk.

As drive changes going forward, once you have the wires re-arranged ready, you could use the Rockstor UI but you would be limited to pool resize add disk and then once that completes do a pool resize remove disk on another drive.

Hope that helps and let us know how it goes.

Do note however that you are currently at the minimum count for btrfs raid 10 and a single drive failure is all that this raid level can handle.

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Thanks for the info!