From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Dorokhine Subject: md not flushing some pages Date: Tue, 15 Mar 2011 10:25:13 -0600 Message-ID: <4D7F92E9.3060405@datagardens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Hello: We are experiencing a strange issue related to md failing to completely flush its array: md13 : active raid1 sdd[1](W) dm-0[0] 3145600 blocks [2/2] [UU] bitmap: 1/384 pages [4KB], 4KB chunk, file: /var/syntropy/bitmaps/md13bm As you can see, md13 has both endpoints connected. However, one page (4KB) refuses to flush (not even overnight). This is md 2.6.3 on kernel 2.6.32.31. We have never seen this problem on kernel 2.6.24, which is what we were using before. md seems to think it's done: [ 985.010761] md: bind [ 985.021776] RAID1 conf printout: [ 985.021782] --- wd:1 rd:2 [ 985.021833] disk 0, wo:0, o:1, dev:dm-0 [ 985.021837] disk 1, wo:1, o:1, dev:sdd [ 985.023589] md: recovery of RAID array md13 [ 985.023609] md: minimum _guaranteed_ speed: 100000 KB/sec/disk. [ 985.023629] md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for recovery. [ 985.023759] md: using 128k window, over a total of 3145600 blocks. [ 1039.515574] md: md13: recovery done. [ 1039.598256] RAID1 conf printout: [ 1039.598263] --- wd:2 rd:2 [ 1039.598270] disk 0, wo:0, o:1, dev:dm-0 [ 1039.598273] disk 1, wo:0, o:1, dev:sdd We did find this bugreport with a similar issue: https://bugzilla.redhat.com/show_bug.cgi?id=680791 However, it mentions that the first broken kernel is 2.6.35.11, but we are using the much-older 2.6.32.31. We have been able to reproduce this issue twice in a row now. Does anyone know why this page is sticking around? Thanks for the advice. Alexander Dorokhine.