RE: [cobalt-users] tar

["Jim Carey" <ozbcoz@xxxxxxxxxxxxxxxx>]

> > I have a backup script that I am using that creates the output 
> .tar.gz files in two steps:
> > 
> > tar -cpPf
> > gzip -9 -S .gz
> > 
> > is there any speed or size difference is using the two step 
> process rather than a one step:
> > 
> > tar -cpvz
> > 
> > method ?
> 
> Speed , yes, tar is mostly disk bound, so there is cpu time left over,
> combining with -z allows the machine to do the compression while it's
> goofing off waiting for the disk...
> 
> However, if the machine is a production server, using all the available
> cpu resources probably isn't a desired goal anyhow ;P
> 
> Size should be identical, assuming you are using the same compression
> level that both default to, but you are using -9 , tar defaults to
> gzip's default, tho you can pass it this info if you want....
> (Set GZIP="-9" before running tar, gzip reads it from the environment)
> 
> You realize that this level of compression almost triples cpu usage, and
> usually gets only a few percent betetr compression ;P
> 
> gsh


Thanks for a great, comprehensive reply :-)

cheers

Jim