mismatch_cnt again

From: Eyal Lebedinsky <eyal@eyal.emu.id.au>
To: linux-raid list <linux-raid@vger.kernel.org>
Subject: mismatch_cnt again
Date: Sat, 07 Nov 2009 11:41:43 +1100	[thread overview]
Message-ID: <4AF4C247.6050303@eyal.emu.id.au> (raw)

For years I found the mismatch_cnt rising regularly every few weeks and could
never relate it to any evens.

I since replaced the computer, installed fedora 11 (was very old debian)
and only kept the array itself (ext3 on 5x1TB raid5). I had the raid
'repair'ed to get it to mismatch_cnt=0.

I thought that I saw the last of these. I had a good run for almost three
months, then last week I saw the first mismatch_cnt=184. It was still so
on this weekly 'check'.

I cannot see any bad event logged.

Are there situations known to cause this without an actual hardware failure?
I know that this came up in the past (often) but I see little recent
discussion and wonder what the current status is.

For the last 6 weeks (my uptime) the machine runs
	2.6.30.5-43.fc11.x86_64 #1 SMP

The raid holds data (no root or swap) used mostly as DVR (nothing heavy).
smartd checks each week and so far no errors. The disks are modern 1yo
"SAMSUNG HD103UJ".

TIA

-- 
Eyal Lebedinsky	(eyal@eyal.emu.id.au)