External USB drive disconnecting itself.

[Chris Ruprecht]

Mikkel L. Ellertson wrote:
> Chris Ruprecht wrote:
>   
>> Hello,
>>
>> I have two external USB drives connected to a FC6 machine. Under heavy
>> load (like gzipping a large file), the drive disconnects itself. I have
>> this message in my syslog:
>>
>>     
> [snip]
>   
>> I have tried two different adaptors, makes no difference. It only works,
>> if I hook up the external drive to the motherboard USB port, but that's
>> USB 1.1 - unusable for this purpose.
>>
>> Any ideas?
>> Thanks,
>> Chris
>>
>>     
> Are these hard drives in USB cases? If so, are they being powered
> off the USB bus? If so, it is probably a power problem. If there is
> an option to use an external power adapter, try that and see if it
> helps. If it is a 2-1/2" drive that will only get its power from the
> USB bus, then it probably has an extra USB connector that is power
> only. If it is long enough, try plugging that into the motherboard
> USB, and the data connector into the USB 2.0 connector. You can also
> try using a powered USB hub instead.
>
> If you are trying to use both drives at once, you are more likely to
> run into power problems. Are you using any other USB devices at the
> same time?
>
> One other thing - check the specs on your USB card, and on the
> devices that you are plugging in to make sure you have enough power.
> There is usually a port limit and a total limit. If you have devices
> that under report their power needs, or have any power-only devices
> plugged in, you may be at or over the total limit.
>
> Mikkel
>   
No, they are externally powered 3.5" Maxtor 320 GB drives. The case is 
an Adaptec USB 2.0 enclosure. They are connected to the 2-port card 
(same card for both drives).

Best regards,
Chris