AnyRAID.
Different drives, one pool.
A new way for ZFS to pool drives of different sizes, so your server can grow a drive at a time.
The 4 TB you started with, the 8 TB you found on sale and the one you haven’t bought yet, all working together.
An open-source project sponsored by Eshtek, creators of HexOS. Engineered by Klara Systems.
Calculator
What could your drives do?
Start from an example, or enter the drives you have.
Your drive lineup
4 drives, sized as on their labels.
Up to 32 drives, 28 more to go. 1 TB = 1,000 GB.
How does that compare?
A standard RAID-Z1 counts every drive as the size of the smallest. AnyRAID-Z1 uses the rest.
Estimates for a new, empty pool, in decimal TB, before compression. AnyRAID-Z is still being built, so they model its published design and may change, and they don’t say which layouts HexOS will offer. See the math and limits
How it works
Think building blocks. Not matching boxes.
The smallest drive sets the size.
In a standard RAID-Z group, every drive counts as the size of the smallest. The extra space on bigger drives goes unused.
Break the space into tiles.
AnyRAID cuts every drive into equal pieces called tiles. A bigger drive simply has more of them.
Parity lives on different drives.
Tiles are grouped into stripes, each tile on a different drive, with one to three holding parity. Lose that many drives and your files are still there.
Coming soon. Be the first to know.
AnyRAID is still being built. Sign up and we’ll email you as it gets closer to HexOS.
Good questions.
Further reading
Where it comes from.
Research checked September 28, 2026.