[4424] in linux-scsi channel archive
Re: Bad blocks: How many?
daemon@ATHENA.MIT.EDU (Karl-Heinz Herrmann)
Tue Jul 21 11:09:39 1998
In-Reply-To: <Pine.A32.3.95.980721120234.88120C-100000@werner.exp-math.uni-essen.de>
Date: Tue, 21 Jul 1998 15:32:22 +0200 (MET DST)
Reply-To: Karl-Heinz Herrmann <k.-h.herrmann@fz-juelich.de>
From: Karl-Heinz Herrmann <k.-h.herrmann@fz-juelich.de>
To: linux-scsi@vger.rutgers.edu
Hello,
I have a Samsung Ultra (non wide) SCSI drive (2GB) and started with
some hundred bad blocks (thats sectors, not tracks. scsiinfo tells
about whole bad tracks by adding a -1 as sector number for that track
and normal bad blocks are adressed as track:sector).
The grown list was clean.
After reinstalling linux I had -- much to my surprise -- 34 grown
defects on that drive. ARRE is off and AWRE in ON (manufacturer
setting), which meens only errors while writing are relocated
silently by the drive.
I had absolutley no warning or error message from the linux kernel.
Obviously while writing to the disk it found some bad blocks and
instead of complaining to the linux kernel the drive just marked it
bad and relocated the block.
I suppose if a read error occurs the error will be reported, since
the ARRE Flag is off.
BTW both my drives (the Samsung and a Quantum Saturn Wide 2GB) have
some hundred bad blocks listed in the manufacturer list. The quantum
has zero grown defects and the samsung now 34.
Since these 34 were recognised imediately after writing about 1.5GB of
data back on the drive I suppose all bad ones are found now and they
seem not to grow any more (2 month since).
So I don't think the 6 hundred bad block of your drive should worry
you. If you have no grown defects but problems with the drive have a
look at your ARRE and AWRE flags (scsiinfo too). Maybe your drive
does no relocation.
But I'm shure if you have a bad media (read/write errors) you won't
get just some timeouts. At least when I tried to get a linux running
on some old MFM drives the kernel started screaming in quite plain
text when read/write errors to the drive occured....
Greetings,
Karl-Heinz
On 21-Jul-98 Dr. Michael Weller wrote:
> Well, at first there are 0 grown defects, so what. Of course, you
> should
> check the AWRE and ARRE settings and the amount of spare sectors to
> use in
> case of defects. If the disk cannot reallocate bad sectors due to
> wrong
> settings there, they won't show up as defects. (actually I'm not
> 100% sure
> if such on the fly defects are added to the grwon list or if you
> have to
> run a format and disk certify process to add to the grown list).
----------------------------------------------------------
E-Mail: Karl-Heinz Herrmann <k.-h.herrmann@fz-juelich.de>
Date: 21-Jul-98 Time: 15:15:36
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