Western Digital hard disks and ATA timeouts

Volker Theile votdev at gmx.de
Fri Nov 7 13:02:34 PST 2008


I can confirm that. Many FreeNAS users had problems with their HDDs  
(e.g. with APM, awake disks to access them after they felt to sleep). 
Increasing timeouts solves the problem in most cases. I think increasing 
the value BUT allowing the user to set it to a preferred value via 
sysctrl would be the best solution. I don't understand why adding such 
an sysctl interface is such an problem for some people. If someone wants 
to set any other value than the default one HE MUST KNOW what he do and 
live with the consequences. There are so many other kernel/system 
variables that can harm the system.

Regards
Volker
<http://dict.leo.org/ende?lp=ende&p=thMx..&search=implications>
Peter Wemm wrote:
> On Thu, Nov 6, 2008 at 11:17 PM, Jeremy Chadwick <koitsu at freebsd.org> wrote:
> [..]
>   
>> As stated, FreeBSD's ATA command timeout is hard-set to 5 seconds, and
>> is not adjustable without editing the ATA code yourself and increasing
>> the value.  The FreeNAS folks have made patches available to turn the
>> timeout value into a sysctl.
>>
>> Soren and/or others, please increase this timeout value.  Five seconds
>> has now been deemed too aggressive a default.  And please consider
>> migrating the timeout value into a sysctl.
>>     
>
> The 5 second timeout has been a problem for quite a while actually.
> I've had a number of instances where I've had to increase it to 20 or
> 30 seconds when recovering from marginal drives.  The longest
> "successful" recovery attempt I've seen was 26 seconds, I believe on a
> Maxtor drive a few years ago.   ("successful" == the drive spent 26
> seconds but eventually successfully read the sector).  Even the IBM
> death star drives could take much longer than 5 seconds to do a
> recovery 5 years ago.  5 seconds has never been a good default.
>
> I think the timeout should be increased to at least 30 seconds.  My
> windows box has a timeout that goes for several minutes.
>
> If there is concern about FreeBSD appearing to hang, I could imagine
> that a console warning message could be printed after 5 seconds.  But
> just say "drive has not yet responded".  But give it more time.
>
> In this day and age we're generally not playing games with udma33 vs
> 66, notched cables, poor CRC support etc.  SATA seems to have
> eliminated all that.  Hmm, it might make sense to increase the timeout
> on SATA connections to 2 or 3 minutes by default.
>   
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