My name is Chris and i am moving to truenas for my homelab. I have 12 WD red drives which are 4x3tb and 8x4tb. i was thinking 2 vdevs(z2) with 6 drives in each. Would this be the best way to go? I am open to suggestion as ZFS is new to me.
Assuming that your drives are CMR, this is a fair way to go.
Note that each vdev is restricted to the size of the smallest member, so 6*4TB + (2*3 TB + 4*4 TB) gives 4*4+4*3 = 28 TB of raw space (use up to about 80% of that).
If possible, get a smaller number of larger drives.
Yes all the drives are CMR. Yes I will lose some room because of the 3tb drives. I wish the 3tb drives were the same as the others but they were bought back when the 3tb were a better value or kind of the sweet spot at time of purchase. I appreciate the help. I also plan on running the boot drive on a wd m.2 nvme drive and maybe mirroring that drive