NonRAID – fork of unRAID array kernel module

What makes this different from regular md? I'm not familiar with unRAID.

unRAID is geared towards homelab style deployments. Its main advantages over typical RAID is it's flexibility (https://www.snapraid.it/compare):

- It lets you throw JBODs (of ANY size) and you can create a "RAID" over them.

- The biggest drive must be a parity drive(s).

- N parity = surviving N drive failures.

- You can expand your storage pool 1 drive at a time. You need to recalculate parity for the full array.

The actual data is spread across drives. If a drive fails, you rebuild it from the parity. This is another implementation (using MergerFS + SnapRAID) https://perfectmediaserver.com/02-tech-stack/snapraid/

It's a very simple model to think of compared to something like ZFS. You can add/remove capacity AND protection as you go.

Its perf is significantly less than ZFS of course.

Ignoring its biggest advantage vs mdraid, or zfs raid:

The ability to sleep all / individual HDDs:

* only keep awake the drives that your actually read data from * only keep awake the drive that your write data too + n parity drives

For home users, that is a TON of energy saving. And no, your "poor" HDDs are not going to suffer from spinning up a few times per day.

You can spin up/down a HDD 10x per day, for 100 years before you come even close to the manufactures (lowest) hdd limits. Let alone if you have 4+ drives and have a bit of data spreading, or combined with unraids nvme/ssd caching layer.

So unlike mdraid or zfs where its a all or nothing situation, unraid / snapraid gives you a ton of energy saving.

And i understand the US folks here do not care when they pay maybe 6 to 12 cent / kwh, but the rest of the world has electricity prices in the 30 to 50 cent / kwh, and it stacks up very fast when you are using < 1watt vs 5/7Watt per HDD/24/7...