Re: MD/RAID time out writing superblock

Mark Lord
2009-09-17T16:17:19Z

Mark Lord wrote:
> Tejun Heo wrote:
>> Hello,
>>
>> Mark Lord wrote:
>>> Tejun.. do we do a FLUSH CACHE before issuing a non-NCQ command ?
>>
>> Nope.
>>
>>> If not, then I think we may need to add code to do it.
>>
>> Hmm... can you explain a bit more? That seems rather extreme to me.
> ..
>
> You may recall that I first raised this issue about a year ago,
> when my own RAID0 array (MythTV box) started showing errors very
> similar to what Chris is reporting.
>
> These were easily triggered by running hddtemp once every few seconds
> to log drive temperatures during Myth recording sessions.
>
> hddtemp uses SMART commands.
>
> The actual errors in the logs were command timeouts,
> but at this point I no longer remember which opcode was
> actually timing out. Disabling the onboard write cache
> immediately "cured" the problem, at the expense of MUCH
> slower I/O times.
..

Speaking of which..

Chris: I wonder if the errors will also vanish in your situation
by disabling the onboard write-caches in the drives ?

Eg. hdparm -W0 /dev/sd?