i Have in one Server an Raid z2 with 8x 20TB, without any issues, its fast enough for a Movie Collection xD
12 Drives is even Cooler, Z2 is really not an issue, but you can even do 4x Z1 in a stripe, which brings more performance.
Z1 on ZFS is not an issue, since there is no write hole (if the server crashes during rebuilding).
I think it was once an issue long time ago, thats why people still think it is one, because zfs is simply so old. But there is none.
However do what you like, i don't think that you need to think about performance anyway, since with 12 Drives, almost in any combination, a 10GBe connection would be anyway the limiting factor.
Code:
pool: HDD_Z2
state: ONLINE
scan: resilvered 23.3G in 00:02:07 with 0 errors on Sun Mar 10 04:44:03 2024
config:
NAME STATE READ WRITE CKSUM
HDD_Z2 ONLINE 0 0 0
raidz2-0 ONLINE 0 0 0
ata-WDC_WUH722020BLE6L4_8LG7XXXX ONLINE 0 0 0
ata-WDC_WUH722020BLE6L4_8LG7XXXX ONLINE 0 0 0
ata-WDC_WUH722020BLE6L4_8LG7XXXX ONLINE 0 0 0
ata-WDC_WUH722020BLE6L4_8LG7XXXX ONLINE 0 0 0
ata-WDC_WUH722020BLE6L4_8LG6XXXX ONLINE 0 0 0
ata-WDC_WUH722020BLE6L4_8LG7XXXX ONLINE 0 0 0
ata-WDC_WUH722020BLE6L4_8LG7XXXX ONLINE 0 0 0
ata-WDC_WUH722020BLE6L4_8LG7XXXX ONLINE 0 0 0
special
mirror-1 ONLINE 0 0 0
nvme-eui.0025384831b022f3-part5 ONLINE 0 0 0
nvme-eui.0025384431414875-part5 ONLINE 0 0 0
mirror-2 ONLINE 0 0 0
nvme-eui.00253844314008c6-part5 ONLINE 0 0 0
nvme-Samsung_SSD_990_PRO_2TB_S7DNNJ0WA01XXXX-part5 ONLINE 0 0 0
The Special VDEV for metadata, are some partitions from 990 Pro's that i use in another zfs pool with mdadm, is a bit complicated, but i have only 4x 990 Pros which i use for a fast VM-Storage pool, and i wanted additionally a special vdev on the HDD Pool.
The special vdev speeds up insanely the Windows-Searching via Samba on Windows etc...
Without a special vdev and that billions of Data on the HDD pool, the windows search would be unusable.
Additional note, stay away from 990 Pro's, these drives are the worst crap ever, they die tooooo fast
Im Replacing like every month or every second month an 990 Pro xD
980 Pros or PM9A3 are a much better option.
Cheers