...I finally got around to adding an 8TB mirrored array to my server
You must know your stuff about hard drives. Are SSD hard drives less reliabe than spinning disk ones?
Someone here recommended avoiding SSDs for storing important stuff.
not richy but ill give my (more or less useless) opinion based on my zfs and raid stuff as well as having SSDs since the intel X-25 SSDs. (2007 or so)
spinners are great for long term storage especially when not powered for long periods of time (years) which admittedly is not common in a NAS. but more importantly if they fail they can often be recovered with specialized equipment.
when a SSD goes its tends to be gone with no real way of recovering data. they are supposed to die in a read only mode but i have had 2 SSDs die in 10 years or so with no way to recover (hooray for backups!). and NO spinners die in that same timeframe although i lost a couple maybe 20 years ago.
the key to long life on spinners is to never turn them off imo.
for me its now its all mirrored drives (desktops) or ZFS level 2 (? i think its Z2 have to check) for important stuff on the NAS (my Z2 is 4 spinner drives any 2 can die) and Z1 (3 SSD drives, one can fail) plus a mirrored set of external USB spinner drives for (more or less) easily replaceable media. and kinda an experiment to see how far i can beat those externals as i do a full scrub every week on all pools. all in a freenas box that backs up to another freenas box thats off line except for that backup process.
so for me, i use spinners for important long term storage. safer as there is a chance of recovery if the drive goes belly up.
also for a NAS
please use ECC memory!
i will be happy to be proven wrong on any of this however.