From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from srv2.trombetti.net ([65.254.53.252]:4273 "EHLO server" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753028AbaGTTX5 (ORCPT ); Sun, 20 Jul 2014 15:23:57 -0400 Message-ID: <53CC1553.1020908@shiftmail.org> Date: Sun, 20 Jul 2014 21:15:31 +0200 From: Bob Marley MIME-Version: 1.0 To: TM , linux-btrfs@vger.kernel.org Subject: Re: 1 week to rebuid 4x 3TB raid10 is a long time! References: In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 20/07/2014 10:45, TM wrote: > Hi, > > I have a raid10 with 4x 3TB disks on a microserver > http://n40l.wikia.com/wiki/Base_Hardware_N54L , 8Gb RAM > > Recently one disk started to fail (smart errors), so I replaced it > Mounted as degraded, added new disk, removed old > Started yesterday > I am monitoring /var/log/messages and it seems it will take a long time > Started at about 8010631739392 > And 20 hours later I am at 6910631739392 > btrfs: relocating block group 6910631739392 flags 65 > > At this rate it will take a week to complete the raid rebuild!!! > > Furthermore it seems that the operation is getting slower and slower > When the rebuild started I had a new message every half a minute, now it’s > getting to OneAndHalf minutes > Most files are small files like flac/jpeg > Hi TM, are you doing other significant filesystem activity during this rebuild, especially random accesses? This can reduce performances a lot on HDDs. E.g. if you were doing strenous multithreaded random writes in the meanwhile, I could expect even less than 5MB/sec overall...