Hi Rob
From a feature point of view, the RAID 5/6 support is complete, meaning that the long missing features drive replacement and scrubbing were added in Kernel 3.19. The latest Rockstor version as of today uses kernel 4.0.2, thus having the above features included.
Is it well tested and bullet proof? No and RAID 5/6 fixes will arrive with the next couple of kernel versions.
The RAID 5/6 write hole is not fixed, btw as this is a fundamental problem in the way RAID 5/6 is currently implemented.
I personally switched to RAID 5 with my 10 TB NAS for home use. Let’s see how this turns out, until now I don’t have any problems. I have a full backup of my data on another machine and an additional offsite backup of my most crucial data so it would be just an annoyance if the NAS completely screws up. And I don’t use it for business…
Having a backup is crucial anyways, as RAID is NOT a backup! Software is never fault free and other things such as flooding, fire or lightning can completely destroy all data.
Regarding the patch you mentioned: Rockstor does not have the manpower to maintain their own kernel versions, and I personally think they should not apply any patches to the kernel. How can you guarantee the patch does not break anything? To me, this is a no-go.
To sum up, I belive you should ask yourself if you can life with a small chance of data loss. If yes try RAID 5/6 and give some feedback here in the forum. If data integrity is crucial to you (business data, …), then I’d wait at least another couple of kernel versions and go with RAID 1, as this is considered stable by the BTRFS guys (http://www.phoronix.com/scan.php?page=news_item&px=MTgzMzM). And dont’s forget to schedule a regular backup.