From: NeilBrown <neilb@suse.de>
To: Jack Wang <xjtuwjp@gmail.com>
Cc: linux-raid@vger.kernel.org
Subject: Re: [RFC] md raid resync counter
Date: Tue, 5 Nov 2013 16:12:55 +1100 [thread overview]
Message-ID: <20131105161255.130a9c52@notabene.brown> (raw)
In-Reply-To: <52776852.3020309@gmail.com>
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On Mon, 04 Nov 2013 10:26:42 +0100 Jack Wang <xjtuwjp@gmail.com> wrote:
> On 11/02/2013 12:48 AM, NeilBrown wrote:
> > On Fri, 01 Nov 2013 13:59:40 +0100 Jack Wang <xjtuwjp@gmail.com> 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.
>
> Jack
NeilBrown
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next prev parent reply other threads:[~2013-11-05 5:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-01 12:59 [RFC] md raid resync counter Jack Wang
2013-11-01 23:48 ` NeilBrown
2013-11-04 9:26 ` Jack Wang
2013-11-05 5:12 ` NeilBrown [this message]
2013-11-05 9:16 ` Jack Wang
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