From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: idle array consuming cpu ??!! Date: Mon, 21 Jan 2008 12:15:27 +1100 Message-ID: <18323.61999.693738.678224@notabene.brown> References: <18323.53904.556620.19761@fisica.ufpr.br> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: message from Carlos Carvalho on Sunday January 20 Sender: linux-raid-owner@vger.kernel.org To: Carlos Carvalho Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Sunday January 20, carlos@fisica.ufpr.br wrote: > A raid6 array with a spare and bitmap is idle: not mounted and with no > IO to it or any of its disks (obviously), as shown by iostat. However > it's consuming cpu: since reboot it used about 11min in 24h, which is quite > a lot even for a busy array (the cpus are fast). The array was cleanly > shutdown so there's been no reconstruction/check or anything else. > > How can this be? Kernel is 2.6.22.16 with the two patches for the > deadlock ("[PATCH 004 of 4] md: Fix an occasional deadlock in raid5 - > FIX") and the previous one. Maybe the bitmap code is waking up regularly to do nothing. Would you be happy to experiment? Remove the bitmap with mdadm --grow /dev/mdX --bitmap=none and see how that affects cpu usage? Thanks, NeilBrown