From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jack Wang Subject: Re: [RFC] md raid resync counter Date: Tue, 05 Nov 2013 10:16:56 +0100 Message-ID: <5278B788.5030304@gmail.com> References: <5273A5BC.5060109@gmail.com> <20131102104808.47834bdc@notabene.brown> <52776852.3020309@gmail.com> <20131105161255.130a9c52@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20131105161255.130a9c52@notabene.brown> Sender: linux-raid-owner@vger.kernel.org To: NeilBrown Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 11/05/2013 06:12 AM, NeilBrown wrote: > On Mon, 04 Nov 2013 10:26:42 +0100 Jack Wang wrote: > >> On 11/02/2013 12:48 AM, NeilBrown wrote: >>> On Fri, 01 Nov 2013 13:59:40 +0100 Jack Wang wrote: >>> >>>> Hi Neil and all, >>>> >>>> Is there anyway to know: >>>> >>>> 1. How often does a raid start to resync? >>> >>> Look at your logs? >>> >>>> 2. How many bytes did it resync? >>> >>> Look at "mismatch_cnt" in sysfs (and multiply by 512). >>> >>> NeilBrown >>> >>> >> Thanks Neil, >> >> You're always very helpful :) >> >> About the second one. As I checked in my system kernel 3.4.51 >> >> when raid is resync: >> cat /proc/mdstat >> Personalities : [raid1] >> md1 : active raid1 dm-1[3] dm-2[2] >> 23762944 blocks super 1.2 [2/1] [_U] >> [==>..................] recovery = 10.7% (2562240/23762944) >> finish=7.5min speed=46565K/sec > > This array is doing "recovery", not "resync". > > "Resync" is when the devices should all contains the same data but maybe > don't due to some error. So md/raid1 checks and fixes the errors. > "recovery" is when a spare has been added and data is being copied onto it. > > >> # cat /sys/block/md1/md/mismatch_cnt >> 0 >> >> cat /sys/block/md1/md/degraded >> 1 >> cat /sys/block/md1/md/mismatch_cnt >> 0 >> # cat /sys/block/md1/md/sync_completed >> 8911488 / 47525888 >> >> mismatch_cnt is 0, sync_completed look what I want? > > "sync_completed" is a number which is somewhat smaller than the number of > sectors that have been be processed by the current > sync/repair/recover/whatever. > > Slightly smaller because it is only updated occasionally. > > I don't really know what you want because you didn't say what you would do > with the information, but it is possible that this is what you want. Thanks Neil for clarification. I think we need track both recovery and resync status, mismatch_cnt and sync_completed are what we want. Regards, Jack > > >> >> Jack > > > NeilBrown >