Facebook has stacks of thousands of spare nodes ready at any moment to replace a failed node. All essential data will be replicated across many different boxes so if a box fails you just replace it with a fresh node and replicate the data there.
This is much different to the consumer usecase where computers are pets and not cattle. A failed filesystem the night before you need to turn in your thesis may have a much larger impact on your life.
Another thing to consider is that Facebook runs btrfs on enterprise hardware (including SSDs with battery backups) which is going to be much more reliable than some chromebook which lives in the bottom of your backpack that you bring on transit every day.
Finally, I will say that the copy on write features of btrfs can result is some wildly different behaviour based upon how you use it. You can get into some very bad pathological cases with write amplification, and if you run btrfs on top of LUKS it can nearly be impossible to figure out why your disk is being pegged despite very little throughput at the VFS layer.
So much FUD in this discussion. Christ Mason talked publicly that they use the cheapest SSDs they can find (even worse things than what he would be willing to put in his laptop), and that they investigate every instance of btrfs corruption. You're saying the exact opposite of the main btrfs guy at Facebook. I wonder who is right...
Who is right, one guy whos reputation relies on something not breaking or a bunch of end users who report the thing broke for them?
I experienced issues with write amplification within the past few months in Ubuntu 22 so it isn’t like all the issues are gone. I do agree that there are less issues now than there was before, but I will still say that btrfs still breaks or behaves unexpectedly much more often than ext4 or xfs.
This is much different to the consumer usecase where computers are pets and not cattle. A failed filesystem the night before you need to turn in your thesis may have a much larger impact on your life.
Another thing to consider is that Facebook runs btrfs on enterprise hardware (including SSDs with battery backups) which is going to be much more reliable than some chromebook which lives in the bottom of your backpack that you bring on transit every day.
Finally, I will say that the copy on write features of btrfs can result is some wildly different behaviour based upon how you use it. You can get into some very bad pathological cases with write amplification, and if you run btrfs on top of LUKS it can nearly be impossible to figure out why your disk is being pegged despite very little throughput at the VFS layer.