Ron, Thanks and I believe I'm having firewall issues with some our the e-mails, so please be patient.
Regards, Tobias Cafiero Data Resource Management Tel: (212) 855-1117 Ron Hawkins <[email protected]> Sent by: IBM Mainframe Discussion List <[email protected]> 03/01/2010 09:35 AM Please respond to IBM Mainframe Discussion List <[email protected]> To [email protected] cc Subject Re: SMS compression cost & size Tobias, There's no magic number. It's pretty much depends on the site, the compression method and how datasets are accessed. It's like asking is there an ideal wheel rim size for every car. Why not raise the bar in some increment and measure the affect. You probably have some idea of where you want to be, so get there in four incremental increases and measure changes in space, CPU usage and IO rates as you go. Ron > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of > Tobias Cafiero > Sent: Monday, March 01, 2010 6:19 AM > To: [email protected] > Subject: Re: [IBM-MAIN] SMS compression cost & size > > Ron, > We compress our GDG's and don't send them to ML1. However at the > time we were trying to save DASD and used the 8 MB And 5 mb values. We > want to raise the bar for Compression, because of DASD issues have > subsided. Is there a ideal threshold for the DASD/Compression size value? > > Regards, > Tobias Cafiero > Data Resource Management > > Tel: (212) 855-1117 > > > > > Ron Hawkins <[email protected]> > Sent by: IBM Mainframe Discussion List <[email protected]> > 02/27/2010 10:45 AM > Please respond to > IBM Mainframe Discussion List <[email protected]> > > > To > [email protected] > cc > > Subject > Re: SMS compression cost & size > > > > > > Reza, > > For me it's not an exception, because I'm in the business of saving IO and > not space )my employer would not like me to save space). > > I see nothing wrong with compressed datasets going to ML2, especially if > they are unlikely to be touched again before they are deleted. ML2 is > usually on media that is cheaper than ML0. > > Actually what I think is quite smart is that they are sending it straight > to > ML2 without migrating to ML1 first. There's almost zero net sum gain > migrating compressed datasets to ML1. > > Ron > > > -----Original Message----- > > From: IBM Mainframe Discussion List [mailto:[email protected]] On > Behalf Of > > R Hey > > Sent: Wednesday, February 24, 2010 12:16 AM > > To: [email protected] > > Subject: Re: [IBM-MAIN] SMS compression cost & size > > > > Ron, > > > > Your example is an 'exception', it was decided to do it for that DS to > gain > > the > > benefit. That's OK by me. > > > > It wasn't decided to COMP all VSAM/PS(FB/VB) DS that are over 5 CYL, > which > > is the case I question. I've seen thousands of GDS, under 5 Cyl, being > > COMP'd, & they quickly go to ML2, so they are not read many times. This > > doesn't make sense to me, if one is short on CPU. > > > > I should have said: > > I don't see why anyone would compress ALL DS under 500 Cyl these days, > > just to save space, when one is short on CPU. > > > > > there is more to compression than just the size of the dataset. > > > > Amen. > > > > Rgds, > > Rez > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to [email protected] with the message: GET IBM-MAIN INFO > > Search the archives at http://bama.ua.edu/archives/ibm-main.html > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: GET IBM-MAIN INFO > Search the archives at http://bama.ua.edu/archives/ibm-main.html > > > > <BR>_____________________________________________________________ > <FONT size=2><BR> > DTCC DISCLAIMER: This email and any files transmitted with it are > confidential and intended solely for the use of the individual or > entity to whom they are addressed. 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