SOLVED Changing number/size of HDD's but maintaining same pool size?

[Gimpymoo]

Hello.

If I build my initial pool with 6 x 2TB drives (12TB total) then down the road, swap out each drive one at a time for 4 x 3TB drives (12TB), will Freenas/ZFS be happy with the 4 x 3TB drives as long as the total size is the same?

Hope that makes sense and many thanks.

 

[kdragon75]

No. The number of drives is a pool can not be decreased, only added to. the only exception is for mirrors, a mirror can be broken. In you case, you would have to backup your data, destroy the old pool, and create a new one. there are a number of great resources in the User Guide that explain ZFS.

 

[Gimpymoo]

Thank you.

I will just start off with 4 x 3TB drives in that case in RAIDZ-2

From what I can gather, 4 drives in Z2 is a good number in terms of performance compared to running 6 for example if I was running smaller drives to achieve the same capacity.

 

[kdragon75]

If you want performance, you should use striped mirrors.