Hi Peter,

We get on average with a mix of unix/os2/WinNT/Novell about 50%
compression. As far as the backup times are concerned I can not really
help you there but it WILL be slower if you use compression - depending on
the
the client's machine it might be a big difference or small. We have some
mean
NT machines that have multiple processors with 512M Ram and they crunch
the numbers like they were bred to...

You can not directly control the amount of processing power used by ADSM,
(Apart from Novell), and thus it is a bit difficult to
predict/control/forecast what
ADSM will need when compressing or not.

Regards
Christo Heuer
ABSA Bank
Johannesburg
South Africa


>Hello Group,
>We are on ADSM V3-MVS, backing up about 300 clients of various platforms,
>including about 110 or so UNIX platforms. We currently allow clients the
>choice of whether to compress. Most of them do not. In order to slow  the
>rate of DASD growth in our primary backup pool, we are considering forcing
>compression from the Server. We would like to get an idea of  how much of
an
>impact we can expect in terms of CPU usage, and backup runtimes. Does
>anybody know of an algorithm that can forecast approximate CPU usage with
>compression turned on? Disk space savings? Or where I can look for this
kind
>of information? Any advice or instructive personal experiences along these
>lines would be greatly appreciated. I would at least like to get an idea of
>how much compression I can force without burying the CPU. Also, whether the
>savings in disk space would be enough to make this idea worth pursuing.
>Thank you!