From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Clements Subject: Re: question about bitmaps and dirty percentile Date: Fri, 31 Jul 2009 14:17:53 -0400 Message-ID: <4A733551.5010408@steeleye.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Jon Nelson Cc: LinuxRaid List-Id: linux-raid.ids Jon Nelson wrote: > On Thu, Jul 30, 2009 at 1:25 PM, Jon > Nelson wrote: >> Then things got weird. >> >> I saw this, which just *can't* be right: >> >> md12 : active raid1 nbd0[2](W) sde[0] >> 72612988 blocks super 1.1 [3/1] [U__] >> [======================================>] recovery =192.7% >> (69979200/36306494) finish=13228593199978.6min speed=11620K/sec >> bitmap: 139/139 pages [556KB], 256KB chunk >> >> and of course the percentile kept growing, and the finish minutes are crazy. > > Weirdness: it ready 199 (or so) and then completed: > > md12 : active raid1 nbd0[2](W) sde[0] > 72612988 blocks super 1.1 [3/2] [UU_] > bitmap: 139/139 pages [556KB], 256KB chunk > > I --fail, --remove the device, and then --re-add it. > > The recovery *starts over*, as if nothing had happened over the last hour or so. > The event counter are very close between /dev/nbd0 (the device here) > and /dev/sde (the core device), within a dozen or so, but the "dirty > percentile" on /dev/nbd0 is big - 18.8%, and unchanging between runs. > It's like the bitmap isn't getting updated, or getting updated > incompletely, or something. > > Does the bitmap only get updated when *all* devices have sync'd??? > I'll let you know in about 2 hours. The bitmap never gets cleared unless all disks in the array are in sync. -- Paul