[Gllug] Tape drive compression

[itsbruce at uklinux.net]

On Thu, Nov 28, 2002 at 05:12:11PM -0000, Darren Beale wrote:
> Hi
> 
> I've just started using Seagate 10/20GB IDE Travan drive to back up my local
> Debian server here. I've had the drive nearly 2 years now, but for some
> reason this is the first time that I've ever used it <shrug>
> 
> Anyway, my question is how does one switch on data Compression?

You don't, you compress the data then put it on.

> ide-tape: Supports data compression - No

Because, as you see, it doesn't do HW compression.

> 
> However the tapes I have are Travan NS 20GB Compatible, which are 10/20GB
> uncompressed/compressed and I thought that the drive could handle this

It's basically a marketing con.  The tapes have a 10GB capacity and if
you achieve a 50% compression rate you can store 20GB on them.

> http://rss.seagate.com/products/srssDrives/STT220000A-M.html (as I said, I
> bought it a while back, but that looks like the same drive)
> 
> So how do I get 20GB out of this puppy? is it a dump option? I see dump -z
> and dump -j (bzip)

Those will do.  Or just pipe the output of your backup process through
gzip or bzip2.

-- 
Bruce

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