> It's possible to create the same amount of redundant storage space with only 6-8 hard drives with RAIDZ2 (RAID 6) redundancy.
I've given up on striped RAID. Residential use requires easy expandability to keep costs down. Expanding an existing parity stripe RAID setup involves failing every drive and slowly replacing them one by one with bigger capacity drives while the whole array is in a degraded state and incurring heavy I/O load. It's easier and safer to build a new one and move the data over. So you pretty much need to buy the entire thing up front which is expensive.
Btrfs has a flexible allocator which makes expansion easier but btrfs just isn't trustworthy. I spent years waiting for RAID-Z expansion only for it to end up being a suboptimal solution that leaves the array in some kind of split parity state, old data in one format and new data in another format.
It's just so tiresome. Just give up on the "storage efficiency" nonsense. Make a pool of double or triple mirrors instead and call it a day. It's simpler to set up, easier to understand, more performant, allows heterogeneous pools of drives which lowers risk of systemic failure due to bad batches, gradual expansion is not only possible but actually easy and doesn't take literal weeks to do, avoids loading the entire pool during resilvering in case of failures, and it offers so much redundancy the only way you'll lose data is if your house literally burns down.
I dislike that article/advice because it’s dishonest / downplaying a limitation of ZFS and advocating that people should spend a lot more money, that may likely not be necessary at all.
I've given up on striped RAID. Residential use requires easy expandability to keep costs down. Expanding an existing parity stripe RAID setup involves failing every drive and slowly replacing them one by one with bigger capacity drives while the whole array is in a degraded state and incurring heavy I/O load. It's easier and safer to build a new one and move the data over. So you pretty much need to buy the entire thing up front which is expensive.
Btrfs has a flexible allocator which makes expansion easier but btrfs just isn't trustworthy. I spent years waiting for RAID-Z expansion only for it to end up being a suboptimal solution that leaves the array in some kind of split parity state, old data in one format and new data in another format.
It's just so tiresome. Just give up on the "storage efficiency" nonsense. Make a pool of double or triple mirrors instead and call it a day. It's simpler to set up, easier to understand, more performant, allows heterogeneous pools of drives which lowers risk of systemic failure due to bad batches, gradual expansion is not only possible but actually easy and doesn't take literal weeks to do, avoids loading the entire pool during resilvering in case of failures, and it offers so much redundancy the only way you'll lose data is if your house literally burns down.
https://jrs-s.net/2015/02/06/zfs-you-should-use-mirror-vdevs...