Re: Uncorrectable errors on RAID-1?

[Phillip Susi <psusi@ubuntu.com>]

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On 12/29/2014 4:53 PM, Chris Murphy wrote:
> Get drives supporting configurable or faster recoveries. There's
> no way around this.

Practically available right now?  Sure.  In theory, no.

> This is a broken record topic honestly. The drives under
> discussion aren't ever meant to be used in raid, they're desktop
> drives, they're designed with long recoveries because it's
> reasonable to try to

The intention to use the drives in a raid is entirely at the
discretion of the user, not the manufacturer.  The only reason we are
even having this conversation is because the manufacturer has added a
misfeature that makes them sub-optimal for use in a raid.

> recover the data even in the face of delays rather than not recover
> at all. Whether there are also some design flaws in here I can't
> say because I'm not a hardware designer or developer but they are
> very clearly targeted at certain use cases and not others, not
> least of which is their error recovery time but also their
> vibration tolerance when multiple drives are in close proximity to
> each other.

Drives have no business whatsoever retrying for so long; every version
of DOS or Windows ever released has been able to report an IO error
and give the *user* the option of retrying it in the hopes that it
will work that time, because drives used to be sane and not keep
retrying a positively ridiculous number of times.

> If you don't like long recoveries, don't buy drives with long 
> recoveries. Simple.

Better to fix the software to deal with it sensibly instead of
encouraging manufacturers to engage in hamstringing their lower priced
products to coax more money out of their customers.

> The device will absolutely provide a specific error so long as its 
> link isn't reset prematurely, which happens to be the linux
> default behavior when combined with drives that have long error
> recovery times. Hence the recommendation is to increase the linux
> command timer value. That is the solution right now. If you want a
> different behavior someone has to write the code to do it because
> it doesn't exist yet, and so far there seems to be zero interest in
> actually doing that work, just some interest in hand waiving that
> it ought to exist, maybe.

If this is your way of saying "patches welcome" then it probably would
have been better just to say that.


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