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Comment by warmwaffles | Hacker News Reader

> The only thing it's missing before I consider it full-featured is stable RAID 5/6. But it looks like that hasn't been forgotten.

I've been running BTRFS RAID6 since 2016 and have only had one issue (arch kernel needed to be rolled back) and never suffered anything catastrophic. It's perfectly happy humming along with a 15x8TB raid array.

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Are you using Raid6 for both data and metadata? If yes, you could just as well have been running raid 0 and having more space and performance out of the same disks. Because of well documented issues, metadata on raid6 is not yet safe in power/hw failure situations. And if you have no safety in those situations, what is raid even for?

(It's perfectly safe to run metadata on raid1 and data on raid5/6.)

With data on raid6 you should be running metadata on raid1c3 or raid1c4, not raid1 nor raid5/6.

Wait, what's wrong with metadata on raid1?

Metadata on raid1 doesn't guarantee the resilience to two-drive failures that raid6 is used for, but metadata on raid1c3 does give you that degree of resilience (with more space overhead, but that's seldom a problem for the metadata).

I'm running RAID6 for data and RAID1 for metadata. Wanted the metadata replicated. So far I've had no HW failure situations and I have suffered a few power outages while I was away from home even though I have a backup battery.

Although these drives have surpassed 50,000 hours of running time, I am fairly certain the day of reckoning is coming, but I have backups and a plan to recover.

I may recover to something not BTRFS. Not sure just yet.

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