~£200 for the drive and it also consumes 10W and not 40. Likely pretty relevant in the long run in the UK.

Cost was another concern, but I’ve not gone down that rabbit hole yet. Using the first online calculator I could find, suggests 10W will cost me 6 pence per day per drive. So about £20 per year per drive. Honestly lower than I thought and not something I’m going to be concerned about

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And when you need more storage use Unraid or mergerFS+Snapraid on Openmediavault. They both allow you to add single drives of any size to add storage capacity and parity.

Thanks for the suggestion but my plan is to stick with TrueNAS

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ZFS is great but it kinda sucks as a home user as expansion only works well when you add 6 or even 12 drives at a time. At least for now.

This is partly why I want to iron things out before buying. I could reasonably see a 32TB pool lasting me longer than the drives lifetime. If it somehow didn’t, I’d just buy a bunch more drives and chuck them in

Because I want “restoring from a backup” to be my last resort in the event of a drive failure. Not my only resort.

The irreplaceable data will all be backed up separately. I’m already doing 3-2-1. But I’d much rather not have everything else get nuked in the event of a single drive failure. And I’ve heard enough stories of a second drive failing while rebuilding that it makes sense to at least consider RAIDZ2, especially for the larger drives.

In the case of the 4TB drives, it’s a trivial amount of money for the extra drive, and in the case of 16TB drives I’d have to buy 4 drives anyway to take advantage of the discount. I don’t see me needing 48TB of storage, so might as well RAIDZ2.

Using RAIDZ1 or RAIDZ2 is for largely the same reason I wouldn’t buy used drives. My personal risk tolerance doesn’t allow for it