[CLUE-Tech] tape backups

[David Anselmi]

Jim Ockers wrote:
> 
> Does anyone have any ideas how tar can be used but still achieve native
> drive speeds on the backup subsystem?  I've seen various schemes for
> buffering the tar input and output using dd (through the system RAM)
> but I've tried that and was underwhelmed by the speed increase.
> 
> Part of the optimization on commercial backup programs is that they
> stream several backups to the tape at the same time.  This means
> that the software has to keep a catalog of what's on the tape and
> where it is - otherwise it can be problematic to restore.

As usual, I don't know but I'll say something anyway :-)

Do you have any idea what it is that can't keep up with the tape?  If 
the bottleneck is disk heads or cpu, writing several streams at once 
doesn't seem to improve things--unless you're writing from several disks.

Could you have tar write into a big fifo?  Or is that the dd bit you 
mentioned?

Maybe amanda has some optimization--it's supposed to be pretty fancy.

Dave