Re: ahci timeouts, retries etc.

[Tim Small <tim@seoss.co.uk>]

Robert Hancock wrote:
>>
>> I'm assuming that the kernel will retry these requests after the sata
>> link has been reset?
>
> Yes.
>
>>
>> The errors appear to be randomly distributed over the four drives on
>> this machine - all are Seagate ST31000340NS with either firmware version
>> SN05 or SN16...
>
> This kind of problem often seems to be due to signal integrity or 
> power problems. For whatever reason, an insufficient power supply (or 
> something like overloading one power cable) can tend to trigger SATA 
> errors as an early symptom..

Thanks for the reply Robert...  The power (and SATA signal) delivery to 
these drives is via a hot-swap backplane which is built-into the chassis 
- I had considered some sort of hardware fault here, and that would seem 
possible, but I don't really have any way to check as I don't have 
access to another one of these machines in order to swap-out parts etc.  
IPMI info looks OK (although I realise this may not catch transient 
power problems at the drives etc.).

The timeouts appear to happen about 4 times per month.  In the absence 
of any other easy strategies, I've disabled SMART data collection on 
this machine, on the off-chance that that makes any difference....

Cheers,

Tim.