Re: umass: AutoSense failed

On Fri, Dec 10, 2010 at 09:40:05AM -0500, Paul Mather wrote:

(reformatted)
> I get something similar to this happening on 8.2-PRERELEASE.  In my
> case, it's not during boot probing or device attachment.  Instead, it
> happens occasionally after boot.  The devices concerned are Maxtor
> OneTouch external USB hard drives.  Every now and then, I will get
> something akin to the following crop up in the console log:
>
> (da1:umass-sim1:1:0:0): AutoSense failed
>
> I have three of these Maxtor OneTouch drives attached to the system as
> part of a ZFS pool.  When I get an "AutoSense failed" message, it is
> usually accompanied by the ZFS pool being marked as faulted.
>
> The Maxtor OneTouch drives are wont to spin down and go into a
> deep sleep after a period of inactivity and appear very slow to
> wake up again when I/O occurs.  I have always assumed that the
> "AutoSense failed" is associated with this---that there is some kind
> of timeout in the FreeBSD stack that this device is exceeding.  In
> fact, sometimes the devices fail to probe properly during boot when
> they are asleep.
>
> This is what the OneTouch normally probes as:
>
> da0 at umass-sim0 bus 0 scbus0 target 0 lun 0 : <Maxtor OneTouch 0121>
> da0Fixed Direct Access SCSI-4 device : 40.000MB/s transfers : 953869MB
> da0(1953525168 512 byte sectors: 255H 63S/T 121601C)
>
>
> Cheers,
>
> Paul.

I had this happen while backing up to two successive previously reliable
UFS USB external disk drives.

Plugging the USB cable into a motherboard USB socket at the back of the
computer rather than a front panel socket made the problem go away.

This might cure the OP's problem too.

-- 
Adrian Wontroba
If it weren't for the opinion polls we'd never know
what people are undecided about.
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