From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Pashaliyski Subject: Re: dm-cache issue Date: Mon, 14 Nov 2016 18:05:18 +0200 Message-ID: References: <884adfe3-ac18-5e37-f4b4-478e5031f35f@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <884adfe3-ac18-5e37-f4b4-478e5031f35f@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: Zdenek Kabelac , dm-devel@redhat.com List-Id: dm-devel.ids On 11/14/2016 05:34 PM, Zdenek Kabelac wrote: > Dne 14.11.2016 v 16:02 Alexander Pashaliyski napsal(a): >> Hi guys, >> >> >> I am in a process of evaluating dm-cache for our backup system. >> >> Currently I have an issue when restart the backup server. The server is >> booting for hours, because of IO load. It seems is triggered a flush >> from SSD >> disk (that is used for a cache device) to the raid controllers (they >> are with >> slow SATA disks). >> I have 10 cached logical volumes in *writethrough mode*, each with 2T >> of data >> over 2 raid controllers. I use a single SSD disk for the cache. >> The backup system is with lvm2-2.02.164-1 & kernel 4.4.30. >> >> >> Do you have any ideas why such flush is triggered? In writethrough >> cache mode >> we shouldn't have dirty blocks in the cache. >> > > Hi > > Have you ensured there was proper shutdown ? > Cache needs to be properly deactivated - if it's just turned off, > all metadata are marked dirty. > > > Regards > > Zdenek > Hi Zdenek, Thank you for your answer. Yes, I am sure. I have modified the lvm2 init script to de-activate all logical volumes and then volume groups, but the issue still persist. Regards, Alex