From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: Is thin provisioning still experimental? Date: Mon, 23 Jul 2018 10:07:34 -0400 Message-ID: <20180723140734.GB28984@redhat.com> References: <20180723140053.GA28984@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20180723140053.GA28984@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Drew Hastings Cc: dm-devel@redhat.com List-Id: dm-devel.ids On Mon, Jul 23 2018 at 10:00am -0400, Mike Snitzer wrote: > On Mon, Jul 23 2018 at 1:06am -0400, > Drew Hastings 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."