I'm building an unRAID NAS on a SM CSE-846 24-bay chassis. I have 25 (24 + 1 as spare) 16TB Seagate EXOS 16 SAS drives incoming. I am new to unRAID and was wondering what will your recommendation om the structure be for my drives. The goal is to saturate read/writes for my 10Gb network. I also want to use the pool to contain always available data for maximizing reads on those. I also want to use the array for my media and the flexibility it provides.

1) How many drives for the ZFS RAIDZ cache pool and how many for the array?

2) How many parity drives?

3) Do I need multiple vdevs for the pool?

Thanks for the help!

Edited September 17, 2025Sep 17 by kevindd992002

For that many drives, you may as well do 2 parity HDs and 22 Array HDs.

you probably arent going to be able to saturate your network read/writes to your array but that's why you should have a large nvme Cache pool that writes to your array and serves as a buffer for incoming content.

read through the guides here to understand everything.

https://docs.unraid.net/unraid-os/advanced-configurations/optimize-storage/zfs-storage/

Ok, so the idea is to create a RAIDZ pool that can saturate 10Gbps read/write "to/from the pool" and not the array. An nVME cache pool is not an option as I need bigger storage and I don't care about random IOPS. I've seen people saturating 10Gbps with a 6-disk RAIDZ1 vdev. My plan is to use a 7-disk RAIDZ2 vdev as a starter (for testing) and dedicate the remaining 17 disks to the array. For 17 disks, is it also recommended to use 2 parity drives out of those?

1 hour ago, kevindd992002 said:

For 17 disks, is it also recommended to use 2 parity drives out of those?

I would, especially considering their capacity.

8 minutes ago, JorgeB said:

I would, especially considering their capacity.

Gotcha. How about for the cache pool, RAIDZ1 or RAIDZ2?

For that disk size, raidz2 may also be advisable, but it will also depend on the backup situation and the importance of the data.