Replace disks in a vddv with bigger drives

[LucaTNT]

Hi everyone,
I'm a noob here and I'm trying to get started on FreeNAS.

Before I buy all the gear required, I have a question.
I understand that if I setup a vdev with three 2Tb drives in raidz1, I'll get ~4Tb of usable space.
Once a drive fails, I can replace it and (given that no other drive fails in the meantime) rebuild everything, not losing any data. Of course the replacement drive needs to be 2 Tb or greater, and here is my question: should I replace it with say a 4 Tb drive, can I make any use of the additional 2Tb data? Of course it would be totally not safe, since there's no redundancy, but it could be useful for less important stuff.
Same applies when the second 2Tb drive fails, can I replace it with a 4Tb drive and use the additional 2Tb? And when finally the last one of the 2Tb fails, I'd like to trash the two 2tb "partitions" and have the vdev expand to take advantage of the whole capacity of my drives, ~8Tb of usable space after parity.

Am I nuts? Is it doable even if partly?

Thank you all guys and greetings from Italy :)

Luca

 

[warri]

No, this won't work. Only when you have replaced all drives in the vdev with bigger ones, you can grow the pool so that it utilizes all the available space.

I suggest you read this presentation on ZFS, which explains the underlying mechanics in detail.

 

[LucaTNT]

Thank you, I read the guide, it was very helpful.

I thought you could tell ZFS to just use half of the disk for the raidz, while leaving the other part available for some other purpose. Never mind, I'll have to find some other solution.

 

[rm-r]

I think though, while changing the drives one by one the pool wont grow - but once all drives are replaced (and equal 4tb size) then the pool will grow in total - right?

 

[cyberjock]

I think though, while changing the drives one by one the pool wont grow - but once all drives are replaced (and equal 4tb size) then the pool will grow in total - right?

Yep.. just like the animated version of my guide shows. When the last disk is replaced the pool size increases. :)