Convert Z1 Pool to Z2

[Trevor68]

Hi,
After 12 months trying out scale I have decided to upgrade my NAS somewhat. Pic of new case included, which has room for 10 3.5" drives, though only easy access for 8.
Currently I have a 4 widex4Tb Z1 pool. Initially I planned on simply buying 4 more 4Tb drives and adding another 4 wide Z1 Vdev to the pool.

Then I started doing some light reading on the subject and my brain exploded, so many options! Clearly this is the time to move to Z2 like everyone recommends, but the exact how eludes me.
Maybe I buy more drives, create a whole new pool, then migrate my data over to the new pool, destroy the old one and reuse those drives as another vdev?

Or maybe I do 8Tb mirrors, then I can just add vdev pairs as needed? Currently I can copy the 7Tb data I have onto 2 external drives if needed.

Once I have a working plan I will do the research required to accomplish it, as I'm still quite nooby at ZFS.

 

[artlessknave]

my first full case for my TrueNAS was a MATX fractal design.

you should be including your hardware for the forum rules, though if all you want is pool topology advice that's probably overkill.

you cannot change raidz level, so you have no choice but to make a new pool
personally, I tend to prefer mirrors, as you can change them in ways that are impossible with raidz, but ultimately the decision is up to you and how you use it. this looks like a home media server? raidz2 can give more space but requires enough drives for that, and the only way to add disks is to add a new raidz. a raidz2 of 4 disks will have the same available space as 2 way mirrors.
if you want a raidz2 of a useful size (6-10), you would need to by enough drives to fill it and have the connections for the new pool and the old pool simultaneously.
in your case, I would recommend mirrors. you can replicate the contents of the old pool over, delete the old pool, and expand the new pool with the old disks. mirrors have the advanage that you can add and remove disks at will. mirrors are also nice in that you only have to replace 2-3 disks for the vdev to expand, whereas raidz you have to replace 4-10 disks to see the expansion. this means raidz2 will be most effiicent when the drives are of similar size, while mirrors can be more efficient with wildly varying drive sizes

also, obligatory *RAID is not a backup*

 

[Trevor68]

Ah that's interesting, I did not realise mirrors could be different sizes! I currently have a HBA card with eight ports, so yes I can create a new pool of say 2x 2 wide mirrors with 4Tb drives = 8Tb roughly, ample for me to move over, and then add the existing disks back for 16Tb total. A decent 6Tb gain in the move.
Yes this is home media, photos and a few docs, all tucked away in both OneDrive and Google One as well. Also home lab for playing with different apps.
I guess once the new pool is up I can just go and fix paths in all my apps to point to the new pool?
Does 4x 2wide mirrors seem like the way forward then?

 

[artlessknave]

Does 4x 2wide mirrors seem like the way forward then?

only you can answer that, but that is what I would do.

 

[Trevor68]

I value your advice, thanks for the headsup!