Hi all,

I have a ReadyNAS which essentially runs Debian and leverages the BTRFS filesystem.

If I am honest, I am a little uneasy at using BTRFS as some consider it not to be stable whereas many say it is perfectly stable / proven.

Nevertheless, what does concern me is the seemingly inability to run a filesystem check like fsck with it like you would with EXT2/3/4.

Anybody have much experience with BTRFS and filesystem corruption... No issues currently but thinking proactive.

Thanks...

I have used it in only two builds, and ran into no issues. To my knowledge, the instability appears in the code for the raid configurations supporting raid-5 and raid-6 features. If you stick with no raid features or mirroring only, the common laptop case, there should be no more problems than using ext4.

I would still like an in-depth check and correct tool for the file system, but we may have to wait a while for that. I monitor the stability section on THIS page https://btrfs.wiki.kernel.org/index.php/Main_Page for changes, and the basic file system on disk has been stable for several months now. (since sometime in 2014 I believe)

OK Thanks... Seems odd that it never had a file checker that EXT2/3/4.

I wonder how well it handles power outages.

It has several kinds of internal checking, and a few one-time checks like fsck runs that can be activated on mount with a command-line option. I suggest hitting the site and doing some reading before using it in any production environment. As always, there is confidence and power in having multiple layers of backups no matter what file system you use.

While I am willing to use it on a non-critical system for convenience, it does not perform as well as EXT4 for server (database) operations. OK for a laptop now, and I expect it to get better, just do not expect it to be fully mature. Yet.

How to put this "gently". fsck is to ensure the filesystem integrity.
Not (necessarily) your files.

That's why lost+found exists - your files might finish up there. Or even just fragments of them.
Not common, but happens. If I have a major "event" (say a power outage) and find any errors, I restore my important systems (in full) without even thinking about it.

btrfs RAID5/6 has been public for a while now and I find it great - but RAID (btrfs or not) doesn't override the need for backups.

For a file server I would expect rait5/6 SHOULD work... and btrfs doesn't work reliably for that (still has problems with power failures, and recovery - check the current status: https://btrfs.wiki.kernel.org/index.php/Status. Still unstable after a number of years, and will not perform repair; so I for one will not use btrfs)

Ext2/3/4 do have a fsck available (same one for all three). Never had problems with md raid5.

You can also check with using LVM.