Hi Joe,

I strongly agree with Matt. I've done then same thing, that is client side
compression and hardware compression on tape. With TSM, with Networker -
I've never seen problems. On the server side all you lose is a bit of tI've 
never seen problems. On the server side all you lose is a bit of tape
capacity. The compression is hardware (sic!) not software. The well known
advice is for software compression - and there it is necessary to avoid
double compression because it takes away resources.

So in your case try client side compression - it might well be that you
gain more than a doubled data rate.

Cheers Peter






"Wholey, Joseph (TGA\\MLOL)" <JWholey AT EXCHANGE.ML DOT COM>@VM.MARIST.EDU> am
30.01.2002 22:07:19

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Thema: Re: low bandwitdth and big files

Matt,

Don't be so sure...  my MVS folks are telling me that there is no way TSM
is over riding their micro-code hardware level compression.  (but I will
double check with them and again as well as with
Tivoli).

With regard to compressing data twice, I disagree.  There's something very
wrong with it.  That's why it is strongly recommended not to do it. (not
just with TSM, but with all data)  Some data that
goes thru multiple compression routines can "blow up" to 2x the size the
file started out as.

And finally, the reason we turn compression on at the client, is to
compress it before it rides our very slow network.  Otherwise, I wouldn't.


Regards, Joe