BtrFS for five years report

Michael Torrie torriem at gmail.com
Mon Aug 28 20:31:16 MDT 2017


On 08/28/2017 05:02 PM, Daniel Fussell wrote:
> On 08/24/2017 08:37 PM, Michael Torrie wrote:
>> 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.
> 
> I wish I had good news, but one of my coworkers ran BtrFS for about a
> year, and the spinning disk just churned all the time.  He finally got
> tired of it and installed FreeBSD with ZFS, just to spite me.  Frankly,
> on his workstation ZFS is no picnic either.  I know of one group (not
> yours) that has a storage server built by
> the-vendor-formerly-known-as-Sun, and I've started hearing the group's
> storage performance has been dropping recently.  I don't know if that's
> because they don't know how to write efficiently, or if it's an artifact
> of ZFS as any particular filesystem ages from use. 
> 
> Myself, I still use XFS and ext4, and I've been toying with zbackup to
> deal with my zfs send/recv envy.

I used ZFS on a Solaris 10 server on a SAN RAID5 array (well proprietary
RAID 6) for 5 years or so and never had any performance issues. Of
course in that time we didn't fill the volumes past half full.  I really
thought it was a nice file system, and I used snapshots all the time.
Snapshots were read-only, but still useful.  Sadly it didn't end so well
either.  At some point after a major Solaris melt down (deadlocked
processes, I/O related), my replacement hit the big red switch and when
it came back up it couldn't even recognize ZFS volumes in the LUNs. So
strange. They even sent the disks to Sun for analysis but they couldn't
even find trace of the ZFS structures the disk was stirred so badly
(disks did not fail; they were working).  Spent many thousands of
dollars with a data recovery firm and they couldn't recover a single
file.  So strange. To this day no one knows what happened or how the
data was so thoroughly scrambled.  Sun's engineers said straight up that
what happened wasn't possible. They pointed fingers at the SAN vender,
and the SAN vender pointed fingers at Sun.

But yeah, it sounds like BtrFS is just no good on spinning disks.  It's
a real shame. I've done a lot of searching but can't find anything on
the BtrFS mailing lists or documentation about what might be happening
or how to fix it.  Not a lot of reporting of performance of any kind
actually.  One would think SuSE users would have a lot of experience
with it by now.  I may upgrade to the latest kernel to see if that helps
but I'm doubtful.

I'll be switching back to Ext4 on my next install, and use borg backup
for backing up to external disks and the cloud--thanks for the
recommendation, Levi.



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