[Discuss] BTRFS

[blu at nedharvey.com (Edward Ned Harvey)]

Anybody using btrfs in production?  I know it says all over it, "not ready
for production" and so forth.  But it's like dangling a big piece of candy
in front of a child with a sticker that says "Do not eat."   ;-)

 

I've had a somewhat bad experience, I'd like to share, and see if others
experienced anything similar.

 

We built a Time Machine server on Ubuntu Oneiric, using btrfs in the
backend.  Snapshots are nice.  But the server was flaky...  I'd say approx
once a week, I'd have to reboot the thing, because for no discernable
reason, performance would grind to a halt, and some processes were
unkillable, and stuff like that.  I suspected btrfs, but didn't have any
really solid indicator.  So, as a guess... Stab in the dark...  I
reformatted the storage ext4.  Ever since, it's been smooth sailing.  That
was about 2-3 months ago.

 

You might conclude that btrfs was to blame.  It's a strong possibility, but
no guarantee.  There was one other change I made, which could also be
influencing things.  I wrote a "shutdown -r now" cron script to run on
Sundays.  To be fair...  I did this while we were still running btrfs, and
it didn't seem to improve stability.  I still found that my logs indicated
the same problems we were having before that script was created...  However,
by introducing that script, the symptoms went away.  Meaning...  I only work
on Mondays and Wednesdays.  So if backups are failing on Monday, users will
complain to me.  By rebooting every Sunday, the backups are always working
on Monday, and the users never complain.  But like I said...  By checking
logs, that doesn't mean the problem went away, just that it went away enough
for people to stop complaining.

 

Since reformatting ext4, as far as I can tell, there are no more problems.
So IMHO, it's a strong indicator the problem was btrfs, but it's not a 100%
indicator.

 

Naturally, you might expect me to remove the Sunday reboot hack.  But I'm
not eager to do that just yet.  Given that things are working now.