Anecdotally, I've found btrfs unreliable. Here is a comment I made a week ago: ---------------------------- Personally, BTRFS feels like it has a ways to go

Anecdotally, I've found btrfs unreliable. Here is a comment I made a week ago: ---------------------------- Personally, BTRFS feels like it has a ways to go before it's ready for prime-time. I've had two major and one minor BTRFS-related issues that have scared me away from it. 1) One of my computers got its BTRFS filesystem into a state where it would hang when trying to mount read/write. What I suspect is that there was some filesystem thing happening in the background when I rebooted the machine. I rebooted via the GUI and there was no sign that something was happening in the background, so this was really a normal thing that a user would do. No amount of fixing was able to get it back, but I was able to boot from the installation media, mount it read-only, and copy the data elsewhere. 2) Virtually all of the Linux servers at work will randomly hang for between minutes and hours. This was eventually traced to a BTRFS-scrub process that the OS vendor schedules to run weekly. The length and impact of the hang seemed to be based on how much write activity happens - servers where all the heavy activity happens on NFS mounts saw no impact, but servers that write a lot of logs to the local filesystem would get severely crippled on a weekly basis. We've moved a bunch of our write-heavy filesystems to non-BTRFS options as a result of this. 3) This is a more minor issue, but still speaks to my experience. I had a VM that was basically a remote desktop for me to use. Generally speaking it would hang hard after a few days of uptime with no actual usage. When I reinstalled it on a non-BTRFS (sorry, can't remember which filesystem I used) filesystem it was rock solid. I have no proof that this had anything to do with BTRFS. All of these were things that happened around a year ago, they may not be a true representation of the current state of BTRFS. But they've burned me badly, so now any use of BTRFS will be evaluated very carefully. In contrast, I've been running ZFS on a couple of FreeBSD servers, with fairly write-heavy loads, and have had no issues that were filesystem-related. Even under severe space and memory constraints ZFS has been rock solid. ---------------------------- The first problem is directly attributable to BTRFS. There is no way a filesystem should get corrupted by a simple user-initiated reboot, regardless of what the system is doing in the background. The second problem is a combination of BTRFS and the distribution. The distribution added a weekly job which did a BTRFS scrub (IIRC), under certain workloads that would completely hang machines for minutes to hours. The time this ran seems to be based on when the OS was installed, so as luck would have it these brought production systems down during business hours. The third problem is something I have no idea about. It could be BTRFS, it could be something completely different, I honestly have no idea.