Kelly French <[EMAIL PROTECTED]> said:
> For me, I'm just tarring up hosts to tape. When the tape develops an
> error, and I use software compression (i.e. -zvvcf /dev/nst0), then I'll
> lose the whole session. If I let the tape drive compress, it won't
> compress as good (like you said), but at least I only lose a file or two.
only if you are foolish enough to use a compressed tar as your backup. use
something like amanda or arkiea (sp?) that will let you compress individual
files before they go onto tape, dont let tar pipe the entire backup through
gzip, one off bit, and you are screwed. a tar of a bunch of little gzips is a
different story.
we have a couple hp's just like the one in question, and we find host-based
multiple file compression to be faster and smaller than drive based stream
compression. we get about 18 or 19 gigs per tape. the only time i break into
20 gig or higher is when i am backing up loads of large text files (sql dumps,
etc)
allan noah
>
> -kf
>
> On Thu, 21 Oct 1999, Stephen Waters wrote:
>
> > i've found that software compression (with our cheesy seagate backup
> > exec s/w anyway..) compresses better than hardware because it is able to
> > reorganize the data in a more compressible manner rather than the drive
> > just compressing whatever hits the buffer.
> > we average just under 18GB per tape w/ full compression, although i have
> > seen instances where it would hit 20GB. it's extremely data dependant i
> > would expect.
> >
> > then again, i could just be talking out of my ass again... :)
> >
> > -s
> >
> > Thomas Seidel wrote:
> > >
> > > I'm sorry this is a bit off-topic, but large raid sets need big backups
;-)
> > > My HP SureStore DAT24 stops after writing 12 GB of data to a DDS-3 tape.
I
> > > suspect there must be something wrong with the compression. To verify
this I
> > > need some additional information:
> > >
> > > - What are the right dip switch settings of the DAT24?
> > > - Did 'mt datcomression 2' really switch the compression on??
> > > - What is the best block size for the dump command???
> > > - Any other topics I have to look for????
> > >
> > > Oh, the box: kernel 2.2.9 & Adaptec AHA-2940 at 10 MB/s narrow sync,
Dual
> > > Processor Board with two PII/400
> > >
> > > Thanx
> > > Thomas
> >
>
>
