From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Thornber Subject: Re: I/O block when removing thin device on the same pool Date: Fri, 22 Jan 2016 16:43:46 +0000 Message-ID: <20160122164345.GA15295@rh-vpn> References: <569F6F08.1040503@redhat.com> <20160121194405.GA22766@redhat.com> <20160122133828.GN26774@soda.linbit> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20160122133828.GN26774@soda.linbit> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development List-Id: dm-devel.ids On Fri, Jan 22, 2016 at 02:38:28PM +0100, Lars Ellenberg wrote: > We have seen lvremove of thin snapshots sometimes minutes, > even ~20 minutes before. I did some work on speeding up thin removal in autumn '14, in particular agressively prefetching metadata pages sped up the tree traversal hugely. Could you confirm you're seeing pauses of this duration with currently kernels please? Obviously any pause, even a few seconds is unacceptable. Having a background kernel worker thread doing the delete, as you describe, is the way to go. But there are complications to do with transactionality and crash protection that have prevented me implementing it. I'll think on it some more now I know it's such a problem for you. - Joe