From: Chris Murphy <lists@colorremedies.com>
To: Roy Sigurd Karlsbakk <roy@karlsbakk.net>
Cc: linux-raid Raid <linux-raid@vger.kernel.org>
Subject: Re: Chances of silent errors?
Date: Tue, 22 Jan 2013 09:28:55 -0700 [thread overview]
Message-ID: <83E6A21C-E6EF-4437-A265-67839431EA4E@colorremedies.com> (raw)
In-Reply-To: <24463267.2.1358852138003.JavaMail.root@zimbra>
On Jan 22, 2013, at 3:55 AM, Roy Sigurd Karlsbakk <roy@karlsbakk.net> wrote:
>> Coming from the zfs world, I've heard a few talk about the chances of
>> "silent errors", meaning the checksum on the drives match, but the
>> data being bad because of matching checksum (aka collisions). Does
>> anyone in here know the relative chance of something like that
>> happening with the checksums of current harddisks? Is the 1:10^14 or
>> 1:10^15 chances for a URE in regard to this, or is that when the drive
>> reports an error, or those two combined?
>
> A follow-up here. I see drive manufacturers report the chance of an URE is 1:10^14 for desktop drives, 1:10^15 for 7k2RPM enterprise drives and 1:10^16 for 10k and 15k enterprise drives (or most do). I was under the impression that "nearline" / 7k2 enterprise drives were the same thing as desktop drives, only with a slightly different firmware (TLER and friends => don't do anything as stupid as going into "deep recovery mode" like some desktop drives do).
>
> Any idea if there's a real difference between the hardware on enterprise and desktop 7k2 drives? Is this 10-fold difference between error rates real, or is it just marketing?
SNIA has said there are differences in ECC between consumer SATA, nearline SATA, and enterprise SAS for some time. They also distinguish quite a few other differences that aren't ECC related, but they don't discuss error rates directly. And this is old information…
http://www.snia.org/sites/default/education/tutorials/2007/spring/storage/Desktop_Nearline_Deltas_by_Design.pdf
Chris Murphy--
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next prev parent reply other threads:[~2013-01-22 16:28 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-21 19:58 Chances of silent errors? Roy Sigurd Karlsbakk
2013-01-21 22:16 ` Roger Heflin
2013-01-21 22:39 ` Peter Grandi
2013-01-21 23:00 ` Chris Murphy
2013-01-22 10:55 ` Roy Sigurd Karlsbakk
2013-01-22 16:28 ` Chris Murphy [this message]
2013-01-22 18:33 ` Roy Sigurd Karlsbakk
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