thanks Bill. jan >----- Oorspronkelijk bericht ----- >Van : Bill Fairchild [mailto:[email protected]] >Verzonden : donderdag , september 3, 2009 04:03 PM >Aan : [email protected] >Onderwerp : Re: What happens in a DS8000 Metro Mirror (PPRC-Sync) config when >the relationship between a volume pair is broken? > >My comments were based on my experience with a 9390 model 6 control unit. I >don't know what the exact mapping is on a DS8000. > >Bill Fairchild > >Software Developer >Rocket Software >275 Grove Street * Newton, MA 02466-2272 * USA >Tel: +1.617.614.4503 * Mobile: +1.508.341.1715 >Email: [email protected] >Web: www.rocketsoftware.com > > >-----Original Message----- >From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of >Jan Vanbrabant >Sent: Wednesday, September 02, 2009 2:50 PM >To: [email protected] >Subject: Re: What happens in a DS8000 Metro Mirror (PPRC-Sync) config when the >relationship between a volume pair is broken? > >Hi Bill, thanks! >Re. <<<PPRC uses one bit to represent a whole cylinder. So if only a single >bit is changed in only one track in cylinder X, then bit X is turned on, which >later will require the copying of all 15 tracks on cylinder X. If a fully >populated EAV is ever available in beaucoup years from now, it will have 16 to >the 7th power cylinders (ca. 268 million), and it will need the same number of >bits, which is 33.5 million bytes. Maybe by then each bit will represent 1,000 >cylinders. >>> > >Is the bitmap on cylinder level, or on track level? >SG24-6787-04 DS8000 Copy Services for IBM System z (6 Februari 2009) >pag. 213 paragraph 15.2? Volumes are in the suspended state when the primary >and secondary storage subsystems cannot communicate anymore, or when the Metro >Mirror pair is suspended manually. In this state, writes to the primary volume >are not mirrored onto the secondary volume. The secondary volume becomes >out-of-sync. During this time, Metro Mirror keeps a bitmap record of the >changed tracks in the primary volume. Later, when the volumes are >re-synchronized, only the tracks that were updated will be copied. >Thruout the redbook at several places, it's always tracks who are mentioned in >relationship with the bitmap. >??? >Jan > > > > >---------------------------------------------------------------------- >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 > >
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