Re: Chances of silent errors?

[Roy Sigurd Karlsbakk <roy@karlsbakk.net>]

> 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?

Vennlige hilsener / Best regards

roy
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Roy Sigurd Karlsbakk
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