Add a new disk drive to raid1

Hello to the community.

It’s been a long time since I posted here so I would like to share with you that my Rockstor installation is running flawlessly all this time.
It has been a very good experience so far and the help I found in this forum contributed to that.

Apart from the time that piled up so did my data on my drives and it seems that a new drive addition is unavoidable.
All my data is currently being stored in 3 disks shaped into a nice Raid1 pool.

I am planning to add an identical (or maybe larger ???) fourth drive to create some more space.

Is there something in particular I should pay attention to or is this a plug ‘n’ play thing?
I thought to physically add the drive to my motherboard and then to add the drive to the pool from rockstor web ui (resize pool). Finally start a new balance.

The fact that I am hoping to not lose any data goes without saying…

Thanks again!

Hello @Sky12016,

You should be able to just Resize the pool and add the disk to it. A BTRFS rebalance automatically gets performed in the background. So, all you need to do is add the disk to the pool using the resize pool option.

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Hello @vesper1978,

So just to break it down:

  1. Power off system.
  2. Plug in new hdd to motherboard’s sata port.
  3. Power on system.
  4. Go to rockstor web ui -> Storage -> Resize pool and add the new disk.
  5. Done!

And the rebalance will take place automatically then, right?

How about the size. Can it be a larger disk or should it be the same size as the other 3?


I just read this thread regarding rebalancing.

Do you think I should disable quotas as well? My disks are 3 x 4TB and I am adding a fourth.

I did some RAID1 and RAID10 rebalancing and don’t remember it being painfully slow. I’d say leave quotas on and start the rebalance. If it is taking too long, turn them off during the rebalance. I didn’t have to stop the balance to turn them off.

And yes, with BTRFS you can have different sizes of disks. I like this website to play without disk sizes:

With BTRFS it does not matter much, which sizes the disks are on RAID1. BTRFS handles it the way, that it just copies the same data to two disks, where the two out of four do not necessarily need to be the same for any other write.

You still should not rely on BTRFS qoutas.

Hello everyone.

Just a quick update for the process.

I powered off my system, I plugged in the new disk, I powered back on and went to Rockstor web-ui and initiated a balance.
It’s been 50 hours since and the balance is on 67%.
I am patient. Hopefully tomorrow it will be completed.
This whole thing however; got me thinking about btrfs and storage maintenance in general.
Under windows I have a defragmentation routine running weekly.

Is it necessary to run balances regularly under Rockstor?
Is it recommended to run manual defragmentation under Rockstor?
Executing any of the above from command line will it have any impact on Rockstor web-ui?

So how do you guys manage/maintain your storage?