Raid 6 not providing expected pool size

I set up a new nas with 4 x 4Tb and 4 X 8Tb drives running in a raid 6 configuration. ( I know rockstor’s Raid 6 is not fully functional at the moment but am willing to test it with a copy of my data )

Other raid programs that I have used and some raid calculators I’ve tried online say I should have a pool around 36Tb in size. Meaning 1 x 4Tb and 1 x 8Tb drives are used for overhead.

But with rockstor it is using 2 x 8Tb drives for overhead and I am only getting a 28Tb pool.

I think this might be another problem with the Raid 6 coding and I am just passing it along.

Please let me know if you think I did something wrong with my setup.

Another thing I just noticed is that on the Disks page under Storage 6 of my disks show power status in red active/idle and 2 disks show in black as unknown. Are the two unknowns the two drives that Rockstor is using for redundancy ? For me the two unknowns are one 4Tb and one 8Tb drives.


as i’m reading your post this is totally expected behavior…

you should read the related wiki article again: RAID


Please show where that specifically refers to Raid 6, since how BTRFS handles “raid” is different to how most other systems do.