Ron, I saw your post and I would like to try out your suggestion. You say that the dsns is compressed at the Primary level and using a Management class it is migrated to Ml2 directly. What software do you use to compress the data on the Primary level?
--- On Wed, 4/21/10, Ron Hawkins <ron.hawkins1...@sbcglobal.net> wrote: From: Ron Hawkins <ron.hawkins1...@sbcglobal.net> Subject: Re: DFHSM QUESTION - MOVING TO DASD FROM TAPE - ML2 To: IBM-MAIN@bama.ua.edu Received: Wednesday, April 21, 2010, 10:31 AM Oops. That should say " It is why one typically gives compressed datasets a management class that bypasses a period on ML1 and sends them to ML2." > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of > Ron Hawkins > Sent: Wednesday, April 21, 2010 8:26 AM > To: IBM-MAIN@bama.ua.edu > Subject: Re: [IBM-MAIN] DFHSM QUESTION - MOVING TO DASD FROM TAPE - ML2 > > Esmie, > > If you choose to compress them then they are compressed. This is the common > practice. Ml1 is often the same media as Primary, so compression is where > one would save space and cost with ML1. It is why one typically gives > compressed datasets a management class that bypasses a period on primary and > sends them to ML2. > > Many sites choose to have ML2 uncompressed as this is already performed by > the tape media, just like you would with DFSMSdss. This saves CPU, but means > the channels are busier. The saving for ML2 is archiving the datasets on > media with a cheaper TCO. > > If you move ML2 to disk you should look at whether compression has to be > enabled again and figure that into your current CPU profile. > > If you were to go with an ML1 only strategy or simply use ML2 Disk, I would > suggest investigating the potential savings of using internal SATA drives, > or if you are using HDS USP or USP-V look at using virtualized midrange > storage - HDS or non-HDS midrange. Depending on when you run primary and > secondary space management, there may be the potential to figure some CPU > capacity savings by using cheaper disk media, leaving compression off for > ML2, and turning it off for ML1. > > Ron > > > -----Original Message----- > > From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On > Behalf Of > > esmie moo > > Sent: Wednesday, April 21, 2010 5:45 AM > > To: IBM-MAIN@bama.ua.edu > > Subject: Re: [IBM-MAIN] DFHSM QUESTION - MOVING TO DASD FROM TAPE - ML2 > > > > Ron, > > > > You mentioned compression. Please correct me if I am wrong. All the dsns > on > > ML1 are compressed? > > > > Thanks. > > > > --- On Tue, 4/20/10, Ron Hawkins <ron.hawkins1...@sbcglobal.net> wrote: > > > > > > From: Ron Hawkins <ron.hawkins1...@sbcglobal.net> > > Subject: Re: DFHSM QUESTION - MOVING TO DASD FROM TAPE - ML2 > > To: IBM-MAIN@bama.ua.edu > > Received: Tuesday, April 20, 2010, 12:46 PM > > > > > > Darth, > > > > The ML1 and ML2 are usually cheaper and lower performance than Primary > > Storage. ML1 cost efficiency is usually achieved through compression, > > whereas ML2 is a change in media. > > > > ML2 Tape can easily be replaced with Tier 2 disk using internal SATA, > > external virtualized midrange storage, or earlier generations of DASD disk > > systems with a reduced maintenance cost (I think Radoslaw did this with > > 7700E). > > > > Ron > > > > > > > > > > > > > > > If I understand this correctly, you're going to have 2 levels of > migration > > > both on Disk? Even if that's possible, what does it gain you? Wouldn't > > > it make more sense to just have an ML1 and then no ML2? And again, I > > > question whether that's even possible with HSM. > > > > > > I do seem to remember this same discussion in the past, so you should > > > probably check out the archives. We're actually going the other route - > > > we're moving to a 'tapeless' virtual tape system & I'm eliminating ML1. > > > > > > ddk > > > > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to lists...@bama.ua.edu 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 lists...@bama.ua.edu 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 lists...@bama.ua.edu 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 lists...@bama.ua.edu 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 lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
