Ditto what everybody else said- can be lots of things.

But I've seen this behavior at exactly ONE customer with LTO4 drives in a
TS3310.
2-drive processes would sometimes take hours.
No errors recorded anywhere, just very, very slow.

Peering through the TS3310 window, I could see (with difficulty) that the
yellow lights on the drives were flashing while this is going on.  If you
look in the IBM LTO book, that light is not supposed to be on (it's weird -
the yellow light means different things depending on whether it's blinking
once per second, twice per second.)

Indicated a firmware error, even though the error was not forwarded to TSM.
And firmware wasn't that old.  But upgrading the firmware fixed it.

W

On Mon, Aug 3, 2009 at 2:34 PM, Mario Behring <mariobehring AT yahoo DOT 
com>wrote:

> Hi list,
>
> The environment is TSM Server 5.5 running on a Windows 2003 box with a IBM
> ULT3580-TD4 SCSI (2 drives) connected.
>
> There is a backup stgpool process running on background for more than 12
> hours (several schedules were missed during this time).
>
> The process is using both drives, one reading the data and the other
> writing, as expected. The problem is that, at some point, both drives stay
> IDLE for more than 20 minutes...then start reading/writing again (for a
> short time I might add).
>
> The process would be long over by now if this was not happening...what
> could be wrong and how can I put the drives to work non-stop, if
> possible...??
>
> Any process that uses both drives in this fashion, like an EXPORT for
> example, is behaving the same way...
>
> Thanks
>
> Mario
>