On Wed, 2005-10-26 at 11:53 -0400, Brent L. Bates wrote:
>      I'm having problems writing and reading from an Sony AIT-3 SCSI tape
> drive.  After boot up, I can write to the tape drive and read from it.
>  However, the next time I try to write to the tape drive, it fails.  I've
> found the following in the system logs at the same time of the failures:
> 
> 	kernel: st: failed to enlarge buffer to 1048576 bytes.
> 
>      I've done some Google searching and have found a number of posts with the
> same problem, but I couldn't find any solutions.  Anyone have any suggestions
> on how to fix this problem?  Rebooting the machine after ever backup isn't a
> good solution at the moment.  Any help greatly appreciated.  Thanks.

Shot in the dark: does explicitly specifying the block size (mt setblck)
help?
And you may want to play with the following options for the st.o module:

buffer_kbs=xxx             the buffer size in kilobytes is set to xxx
max_buffers=xxx            the maximum number of tape buffer set to xxx
max_sg_segs=xxx        	   the maximum number of scatter/gather
                           segments

(as per drivers/scsi/README.st)