Re: [atomic-devel] Btrfs + overlayfs

[Matthew Miller <mattdm mattdm org>]

On Fri, Jul 21, 2017 at 10:16:16AM -0600, Chris Murphy wrote:
> This is a followup to this:
> Figure out comprehensive strategy for atomic host container storage
> https://pagure.io/atomic-wg/issue/281
> 
> I said I'd post something to the Btrfs devel list about combining
> Btrfs and overlayfs; and I got back a couple interesting replies
> including, "We've been running Btrfs with Docker at appreciable scale
> for a few months now (100-200k containers  / day )"

Chris, my concern with Btrfs is over kernel engineering support. As you
know, this has come up repeatedly on the Fedora devel list over the
years and always the devs give the recommendation to not make it the
default for anything — until basically we were asked to stop asking.

Meanwhile, I don't see Red Hat making large moves around Btrfs, while I
*do* see significant investment in XFS, including some interesting new
projects like Stratis *. I know I've been waiting for Btrfs since
FUDCon Boston 2009, but at this point XFS really seems like it's the
better choice for the forseeable future.




-----
* Stratis:


https://vault2017.sched.com/event/9WQV/stratis-a-new-approach-to-local-storage-management-andy-grover-red-hat
https://stratis-storage.github.io/StratisSoftwareDesign.pdf
https://github.com/stratis-storage


> 
> https://www.spinics.net/lists/linux-btrfs/msg67308.html
> 
> Also, installing
> Fedora-Workstation-ostree-x86_64-Rawhide-20170714.n.0.iso then
> converting to Btrfs still uses overlayfs for all the rpm-ostree
> related commands that add in layers; so I've been using that
> combination on a test machine and didn't realize it until now, and I
> haven't had any problems so far.
> 
> Anyway, in the pagure issue mentioned above, what keeps coming up are
> a bunch of complexities with partitioning, LVM, and fs resizing
> limitations. All of the mentioned dilemmas go away with Btrfs. The one
> dilemma Btrfs adds is quota support is definitely still a work in
> progress, sometimes bringing performance penalties with bigger file
> systems. This is better qualified in the spinics message.
> 
> 
> 
> -- 
> Chris Murphy
> 

-- 
Matthew Miller            mattdm mattdm org             <http://mattdm.org/>
Fedora Project Leader  mattdm fedoraproject org  <http://fedoraproject.org/>