On Wed, 2009-01-07 at 17:57 +0100, Ralf Gross wrote:
> T. Horsnell schrieb:
> > Ralf Gross wrote:
> > > Ferdinando Pasqualetti schrieb:
> > >> I think you should use /dev/random, not /dev/zero unless hardware 
> > >> compression is disabled in order to have more realistic figures.
> > > 
> > > This wouldn't be a good idea, /dev/random or /dev/urandom are just too
> > > slow in generating random data. To test the nativ speed of the  drive
> > > creating a file from /dev/urandom and writing this file then from
> > > tmpfs or a fast disk to the drive would be much better.
> > > 
> > > 
> > > Ralf
> > 
> > Personally, I'd use /dev/zero with compression turned off.
> > Then there's *nothing* between the data-source and the tapedrive.
> 
> Yes, but most people use hardware compresion with LTO drives. Sooner
> or later he has to test the drive with compression.
----
funny thing is that amanda developers are adamant that you disable
hardware compression and use software compression instead.

Obviously it takes longer and more cpu power to compress the files in
software before storing them on the tape and if you leave hardware
compression on and use software compression too, the files probably grow
in size.

Commercial backup software just seems to always use hardware
compression.

Craig


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