ATA drive failure with 4.6.2 & 250GB drives

[Bill Vermillion]

"Ang utong ko ay sasabog sa sarap!" exclaimed
freebsd-stable-request at freebsd.org while reading this message on
Wed, Oct 15, 2003 at 12:00

> ------------------------------

> Message: 12
> Date: Wed, 15 Oct 2003 08:53:32 -0700
> From: "Kevin Oberman" <oberman at es.net>
> Subject: Re: ATA failure with 4.6.2 & 250GB drive? 
> Message-ID: <20031015155332.A34435D07 at ptavv.es.net>

[mucho deletia - wjv] [accidentally clipped this attrib]

> > I'll probably pull it out and run the Maxtor diagnostics over
> > it to see if they turn up anything interesting. Do you think
> > a low-level format would be useful?

> > Very annoying to have two of these things die almost
> > immediately after installation. Does not encourage me to buy
> > more Maxtor products in the future :-(

I've really had no problems with Maxtor going back to ESDI drive
about 1990.   As to die immediately after installation?  Infant
mortality is a fact of life in anything electronic.  Items which
pass manufacturing specs may fall over dead in the first few hours
of use.  If you can make it past 100+ hours then most often the
devices will last to their specified life.

I use the current ATA drives in some servers.  However I always use
the 'server' type drives from Maxtor - those are the ones with the
3-year warranty - and last time I looked that was only on 120GB 
and above drives with 8MB cache.  I've never used the 1 year
warranty drives.

> FWIW, the drive I ran into this on was an IBM (now Hitachi). Back
> blocks on a hard drive are unavoidable. Plating techniques are amazing
> (especially when I worked for so many years with coated media), but
> they are simply not perfect, especially with the magnetic domain size
> on modern drives.

And as someone who started with coated media in broadcasting
and recording I'm still amazed as how well magnetic recording works
given all the constraints. 

> This is more likely an indicator of inadequate testing of the
> drive. Normally the bad spots on a platter should be detected
> and re-mapped before the drive is shipped. Every platter has
> bad blocks, but they really should be caught before the unit is
> shipped. The issue is marginal areas that pass the tests when
> the drive is first turned on, but produce too weak a domain
> to be detected when the drive has aged a bit. These should be
> caught before shipping, but will continue to crop up during
> normal use as the heads age. As long as they are detected
> during a write attempt, you never see them. But, if an already
> written sector is becomes unreadable, there is not graceful way
> to recover.

Not just head aging, but electronics burning in and slight
sensitivity changes.   Most decent drives today have error
correction routines to recover data that becomes unreadable.
Typically when data is hard to read the ECC is cranked up to a
level to read it and then the data is read, and rewritten to good
sections.  The operative word is descent.  This process started
in the SCSI and ESDI drive era and I watched on drive gradually add
errors after recovery until the controller failed - not the drive.
It ran 7 years and 2 months 24x7 as a small news node.  That was
a Maxtor.  After about 4 years I decided I'd just see how long it
could go.

> I don't know much about ATA disks, but they probably have ECC to
> further reduce the chance of this happening, but failures still
> happen.

> I doubt that a low-level format will help any. The drive diagnostic
> should re-map the bad region and the drive may continue to operate
> well for years. The sign of impending doom is when this thing happens
> repeatedly. That usually means that the disk's days a near the end.

Actually the low-level format using the utilites you get from the
drive manufacturer - and sometimes this will require a download
from the manufacturers site - work amazingly well.

This is a true low-level format.  What many people call low-level
from MS experience is actually a high-level logical format 
of a disk that is applied on top of a low-level format.

The mfr utility disks do something very similar to factory
formatting and will go through an write/test each block and
contruct new bad track tables.

I picked up a handful of untested pulls as-is drives at a local
computer show.  Not a single one would perform the MS "low-level"
format, and some could not be recognized.  After getting the mfr
disks and running those 3 of the 5 came back and were just fine.

That was a symptom of the low-level information becoming corrupt
and could easily happen with a power spike or surge occuring during
a write cycle.  I have not found that a failure to write/read
is neccesarily a 'sign of impending doom' - though that is
what has beem propogated by those who started with MS operating
systems.   

A hangover from those days also seems to be 'reformat the drive to
refresh the format' - and there were companies that made software
to do that.  While that may have been a workable [but maybe not
needed] process in the days when drive heads used stepper motors 
and you could have physical wear on the stepper mechanism so the
drive heads would shift position over the years that has not been
needed for year.

> This is from someone who was very involved in disks back in the 70's
> and 80's, but who has never worked much with IDE/ATA disks and whose
> major experience was with SMD drives. I like to think I still know a
> little about them, though I may simply be growing senile.

I know about the feeling of getting senile.  My first HD was
an 8" Shugart SA-????  - 8" - 8MB.  And I have a 5.25" Shugart
floppy with a handwritten serial number that came from the first
run of pre-production 5.25" floppies ever made.  Before computers
I lived with magnetic tape in broacast/recording.  Things surely
have changed from the days of the first 5.25" HD that was
5MB and listed for $2500 - the original Shugart ST-512 - hence the
interface name that lives in it's memory.

[line below retained for reference]
> End of freebsd-stable Digest, Vol 30, Issue 3
> *********************************************

Bill
-- 
Bill Vermillion - bv @ wjv . com