Ed, That's a straw man! How many decades has it been since anyone made a box with Dual Copy?
We are talking about instant split capabilities of "In system replication" - Shadowimage, Flashcopy, Timefinder and Snapshot. We are not talking about alien laser beams - we are talking Disaster Tolerant Storage (that's a RAID Advisory Board specification). Are we serious? For more than ten years we have been buying storage that takes our mainframe data and cuts it up onto millions, billions and trillions of FBA blocks, which are then striped, chunked and copied all over significantly less disk drives than MVS thinks it has. And how do we access this stew of data? Through maps and pointers. That's how. And because a copy is created through maps and pointers we are debating that this is some sort of additional risk from a disk drive failure? Well get it right - in the same parity group it has to be two disk drive failures for RAID-1 and RAID-5 (HDS, IBM and EMC), and three disk drive failures for RAID-6 (HDS and SUN/STK). Instead of talking about alien laser beams, do your homework with MTBF and MTTR (sparing time) to figure out those probabilities. Ron > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On > Behalf Of Ed Finnell > Sent: Monday, 13 March 2006 2:49 AM > To: [email protected] > Subject: Re: IXFP No Longer Supported > > > In a message dated 3/12/2006 12:19:13 P.M. Central Standard Time, > [EMAIL PROTECTED] writes: > > It would have to be a very precise alien laser beam. > > > > >> > Murphy is an awfully good shot! Spent many hours recovering disk failures > in > dual copy/PPRC where the primary failed during the process. > > ---------------------------------------------------------------------- > 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
