how would you spend $1000 on a server?

[Lennart Sorensen]

On Mon, Jul 19, 2010 at 11:23:49AM -0400, D. Hugh Redelmeier wrote:
> | From: Lennart Sorensen <lsorense-1wCw9BSqJbv44Nm34jS7GywD8/FfD2ys at public.gmane.org>
> 
> | > I like Samsung, because they have "enterprise" specs (whatever that
> | > means) at "consumer" price:
> | >     - 1 in 10^15 non-recoverable error,
> | 
> | It sounds nice, but I am still going to stick with raid, and I am really
> | looking forward to btrfs stabalising so we can have a filesystem with
> | CRC block checks.
> 
> As I understand it, most drives "intended for consumer price points"
> cannot be told to limit the time of error recovery.  This makes them
> poor for RAID.
> 
> When an error is detected by the drive, it may take a
> long time trying to recover.  The RAID system may interpret that as
> the whole drive failing.  The RAID ability to make up for a sector
> loss is thwarted.  Adding the drive back to the RAID array takes
> rebuilding, during which time the redundancy is lost.  The rebuild
> time is very large with current large drives.

That is certainly true.  It might take long.  Fortunately it seems it
doesn't usually.  WD does have the raid edition drives (for a bit extra
cost) which have limits on recovery time for that reason.

> The manufacturers wish to introduce price differentiation: I think
> that enterprise and similar consumer disks are essentially the same
> except for a firmware difference (giving economies of scale).  This
> firmware difference makes the consumer drives unsuitable for RAID use
> (allowing them to charge higher prices for the enterprise version).
> <http://en.wikipedia.org/wiki/Price_discrimination>

Certainly true.  Just a firmware difference in the case of the raid
support.

> If I remember correctly, Samsung is the only manufacturer not to do
> this at the moment.  Please confirm this information before you act on
> it.
> 
> I think that this wikipedia article is poorly written and wrong, but
> still useful:
>  <http://en.wikipedia.org/wiki/Time-Limited_Error_Recovery>
> We should do research and fix it.

Well it seems that most WD drives can be reconfigured (using a free DOS
utility) to turn on or off time limited error recovery.  I guess you
don't have to buy the more expensive ones just for that then.

Seems it doesn't work on newer drives though.

-- 
Len Sorensen
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