[dm-devel] Is thin provisioning still experimental?

[Mike Snitzer]

On Mon, Jul 23 2018 at 10:00am -0400,
Mike Snitzer <snitzer at redhat.com> wrote:

> On Mon, Jul 23 2018 at  1:06am -0400,
> Drew Hastings <dhastings at crucialwebhost.com> wrote:
> 
> >    I love all of the work you guys do @dm-devel . Thanks for taking the time
> >    to read this.
> >    I would like to use thin provisioning targets in production, but it's hard
> >    to ignore the warning in the documentation. It seems like, with an
> >    understanding of how thin provisioning works, it should be safe to use.
> 
> It is stale.  I just committed this update that'll go upstream for the
> 4.19 merge window, see:
> https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-4.19&id=f88a3f746ff0047c92e8312646247b08264daf35
> 
> >    If the metadata and data device for the thin pool have enough space and
> >    are both error free, the kernel has plenty of free RAM, block sizes are
> >    set large enough to never run into performance issues (64 MiB), all of the
> >    underlying hardware is redundant on high performance NVME (no worries of
> >    fragmentation of data volume)... is it still unsafe for production? If so,
> >    can you shed some light on why that is?
> 
> It is safe.  You do just want to make sure to not run out of space.  We
> now handle that event favorably but it is best to tempt fate.

I meant: "... but it is best to _not_ tempt fate."