In all of my experience with ADSM it is better to let the tape device
do the compression. It will obviously take longer to do a backup, when
you are using software to do the compression, verses hardware.

Mark

Robert Cross wrote:
>
> Eric-van.Loon AT KLM DOT NL wrote:
>
> >I have several Sun Solaris clients which show a significant performance
> >difference when using compression. The largest client is a Sun E10000, so
> >quite a large machine with a lot of CPU power.
>
> I'm green with envy!
>
> >When I'm not using compression I see a 7 Mbytes/sec performance over 100 Mb
> >Ethernet. When using compression I measure no more than 0.5-1 Mbytes/sec.
> >Has anybody seen this behavior too?
>
> We have two systems that I tested with ADSM, one is a SPARCserver1000 with six
> processors running Solaris 2.4 and the second is a SPARCstation2, single
> processor,
> running Solaris 2.6. Both systems talk to an RS6000/SP2 ADSM v3 server over
> Token
> Ring (don't laugh - we're replacing this)
>
> However with the SS2, turning compression off slashed the backup time by half,
> 6GB of
> data taking 2 hours as opposed to over 4 hours with the compression on.
>
> For comparison the SS1000, which has compression turned on, takes roughly the
> same
> amount of time (2 hours) to backup only 1.5GB of data. We were hesitant about
> reading too much into
> this since the SS1000 and SS2 run different clients, (V2 and V3) respectively.
> Additionally we
> had assuming that the network was probably throttling back the ADSM backup
> performance.,
> I'm going to try a test fairly soon  with the compression off on the SS1000 -
> I'll let you know what
> happens.
>
> Bob Cross.
>
> We will be moving the Solaris 2.4 system to Solaris 2.6 fairly soon, and
> updating to V3 clients.

--
ned!
ned!