Add a ned disk so I can have more space

[pitzav]

Hi I am sorry if this written somewhere in the forum. I did search for it but because I am new I am not sure if I will do it correctly without losing my data.
I had a 3x4tb nas system with one disk redundancy. I am running out of space now and have 360 gb available. I bought one more wd red drive so I can extend it but when I go to the extent the pool it doesn't let me. I read somewhere that I had to know that I will extend it from the beginning and if I do it incorrectly I will make that new dsisk the redundant one if that disk fails I will loose all my data. Also, read somewhere something about vdevs which I have no clue what they are and where to find them.

My end result is that I want to extend my pool by 4tb which is the new drive I bought. Is this possible or I have to buy and add 3 total drives again because this is how I started the pool? BTW even if I could buy them my motherboard does not support so many sata and I guess I will need to buy a PCI sata card.

Attached is a screenshot of where I am and terrified :)

Thank you in advance.

 

[adrianwi]

When you created your zpool, you actually created a vdev containing your 3 x 4TB drives. You can't change that vdev once it has been created.

You can increase the size of the zpool by adding more vdevs, but you need to consider the redundancy for the new vdevs. Adding a single drive vdev into your zpool (i.e. 1 vdev of 3x4TB and 1 vdev of 1x4TB) wouldn't be advisable. If that new vdev drive failed you would lose the whole pool!

Adding another 3x4TB vdev would probably be the easiest solution, and provide double the capacity with the same level of redundancy you have now (1 disk tolerance on each vdev). That said, with 6 drives, one RAIDZ2 vdev would probably be a better solution, offering the same capacity with a 2 disk tolerance.

Any of the options which involve reconfiguring the current vdev will need you to find some way to move the data first through, as this would lose all data from the drives! There have been murmurs about being able to expand RAIDZ1 vdevs (which is what you have) for some years, but I still think that's some way off.

 

[pitzav]

I see, thank you for your reply. Not at all like I have imagined it with just my pure logic. I thought that if I needed more I would just add a disk.
So If I need to make it from scratch by buying 2 more so I can have 2 redundant disks and 4x4TB =16TB total storage. What should I do with VDEVS so next time I want to keep adding disks one by one to increase my storage gradually?

 

[adrianwi]

You can't change a vdev once you've created it.

If you had 6 drives you could create one RAIDZ2 vdev (so 6x4TB) which would give you the capacity of about 16TB (slightly less once you take into account some overheads) and a tolerance of 2 disks failing without loss of any data.

This is quite a common configuration I think for home use and how my machine is configured, albeit I have 8x8TB drives in one vdev and one zpool

 

[pitzav]

So If I want to increase my space without having to add more drives is either start again each time with the new disks or replacing one by one my disks with a larger one until all are replaced with a bigger one right?