[CLUE-Tech] Slow DLT performance

[David Anselmi]

Casagrande, Steve wrote:
> While it's been years since I've done tape stuff, I do recall that if you
> can't feed the tape drive with enough data to keep it streaming, it will
> stop, rewind, and start again, which absolutely kills throughput.
> 
> Perhaps you could write a small program to dump random data to the drive,
> and measure throughput?  This would take the disks out of the equation.
> (Maybe there's a conflict between the RAID controller and the tape
> controller...)

ADIC sent me the mt program compiled for Windows to troubleshoot a Sony 
AIT drive.  It seems you can get it from the cpio or mt-st packages.  mt 
does various tape operations (eject, rewind, read, write, etc.).  It may 
be the thing to use to talk to the tape drive.  I think it will tell you 
bytes written and elapsed time...

Does reading from the tape go any faster?

I'd think that dd or cat or such would work with the tape block device, 
but since they don't understand rewinding and so on maybe mt is better.

Dave