Re: [Dump-users] performance difference??

[Ken G. <ke...@pe...>]

> Investigate the mt / mt-st commands to check what density you're writing 
> to tape at, and whether tape drive compression is enabled or not.
> # mt -f /dev/nst0 status
> 
> On some systems stinit(8) configures tapes at boot. Compare the 
> /etc/stinit.def (if it exists) on both systems.
> 
> You may find one system is writing fixed size tape blocks, and the other 
> at a variable block size. Try forcing the CentOS machine to a variable 
> block size as with some drives this really helps streaming throughput:
> # mt -f /dev/nst0 setblk 0
> 

Thanks for your suggestions.

Never even heard of the "stinit" program, even thou
it was not in use on either system. I'm using it now.
tapeinfo is/was also usefull.
After what seems to be several more hours of
messing with this I'm no closer to
increasing transfer rates.
compression is on, ait density, streaming, etc.

The difference in transfer rates seems consistent with
compression vs no compression.

I'm beinging to suspect the tape drive itself.
I have not swapped tape drives yet, but will tomarrow.
That should answer if it's the tape drive or not.

Thanks again.
I'll just keep poking as time permits.