UnRAID array rebuild with less drives

Bluecube · 4 Oct 2017 at 19:28

I currently have an unRAID server with five 2Tb hard drives for storage. I added a 6Tb parity drive and have removed one of the 2Gb drives and added another 6Tb drive. An array rebuild is now in progress. All good there (so far - touch wood, etc)

I will be adding a further two 6Tb drives over the next couple of days. The whole idea is to move from 5x2Tb to 3x6Tb (plus the parity drive of course). However's it dawned on me that I'm going to have 2x2Tb that are still part of the array with data on them. How do I ensure the data is on the next drives? Remove them one by one with an array rebuild after each removal?

TIA

BlizzardX · 5 Oct 2017 at 01:48

Couldn't you just mount the 2 2tb drives and then move them yourself to a new drive?

Bluecube · 5 Oct 2017 at 06:33

UnRAID spreads data across multiple drives like a RAID configuration. While the drives can be read individually, I’m not sure if it’s possible to move data between drives... I’m going to look into this further though as it’d make a big difference time-wise if it’s possible.

ubern00b · 5 Oct 2017 at 09:31

If I recall correctly you can eject a disk from an array which will initiate a migration of the data on the disk to other disks on the array.

https://wiki.lime-technology.com/Shrink_array

PiKe · 5 Oct 2017 at 09:46

You can use the unbalance plugin to move the data to the drives you want, then run New Config and re-create it with just the drives you want to use.

Unlike a normal RAID system, you can do this without any data loss and the data isn't striped over different drives.

Bluecube · 5 Oct 2017 at 10:40

ubern00b said:
If I recall correctly you can eject a disk from an array which will initiate a migration of the data on the disk to other disks on the array.

https://wiki.lime-technology.com/Shrink_array

Eject in software as opposed to physically removing it? Because I completely removed the first disk and replaced it with the 6Tb drive. Parity is being rebuilt right now so I assumed the missingdata is being added to the new drive? You’ve got me a bit worried now!

PiKe - thanks for that info. Sounds ideal! I’ll look into that.

ubern00b · 5 Oct 2017 at 11:55

Bluecube said:
Eject in software as opposed to physically removing it? Because I completely removed the first disk and replaced it with the 6Tb drive. Parity is being rebuilt right now so I assumed the missingdata is being added to the new drive? You’ve got me a bit worried now!

PiKe - thanks for that info. Sounds ideal! I’ll look into that.

Yes, eject in software. The way you are doing it is correct as it is rebuilding from parity however at the moment you are just replacing drives for larger versions. You want to consolidate a drive or two so need to move the data from those drives onto one of the other drives so you can't just remove the disk and have it rebuild from parity. PiKe's solution is bang on actually.

Bluecube · 5 Oct 2017 at 12:21

Ugh. Wonderful... I’ll have to see how this parity rebuild has gone before I can do anything else. It does sound as if I’ve made a boo boo.

neodude · 6 Oct 2017 at 10:27

Just log in via ssh and move the files between drives using midnight commander.

PiKe · 6 Oct 2017 at 10:48

More annoying than using unbalance.

neodude · 6 Oct 2017 at 14:56

Each to their own. I don't find it annoying

Avalon · 9 Oct 2017 at 17:41

I recently had to re-juggle my storage, the Unraid wiki describes both official methods of doing this.