BtrFS for five years report

Michael Torrie torriem at
Thu Aug 24 20:37:43 MDT 2017

So a few years ago we talked on this list about BtrFS and how I was
using it without issues.  Well, unfortunately, I've about reached the
end of the road with BtrFS, at least on spinning disks (still working
fine on the laptop SSD).  Essentially performance has completely tanked
after running it for years.  My largest partition is only about 75%
full, and I've tried all the different commands to rebalance the trees,
defrag files, etc.  Essentially any disk I/O, particularly swap just
kills BtrFS performance on the rest of the disk.  If I do a read/write
test on a large file I get pretty normal through-puts (although writes
are quite slow), but if the I/O is random, things just slow to a crawl
and load average spikes.

So I'm soon going to switch everything back to Ext4.  I'll miss
snapshots (and the way BtrFS does it vs ZFS), and I do like the peace of
mind that BtrFS offers against bit rot, but my system is pretty unusable
unless I restart firefox every couple of days (it *still* leaks like a
sieve).  ZFS isn't really an option because of the amount of RAM it
requires, though I may play with it...

To top it off, Red Hat has quietly deprecated BtrFS in their RHEL line,
removing it from the latest point release, which indicates to me things
are not well with it.  SuSE has apparently bet the farm on BtrFS, as
they have features of their distro that depend on it, so it will be
interesting to see how it pans out.

Anyway, thought I'd give an update, and I'd like to hear of anyone who's
using BtrFS on spinning disk and finds it's working well, or if anyone
knows how to fix my BtrFS problems!  There's so much potential with BtrFS.

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