We've used DWDM between data centers for years. We do DASD mirroring (XRC), remote tape, and FCTC. DWDM is pretty reliable. It hiccups now and then. XRC suspends and later resumes. Tape jobs fail and need to be rerun. Network connections drop and eventually reconnect. All in all the occasional disruption is worth it.
OTOH I would not entertain running a parallel sysplex over DWDM. Even we could squeeze into the 100 KM limit and run 'bare fiber' without DWDM, I still would not do it. There are too many environmental vagaries out there when you depend utterly on miles of fiber that you cannot control. Meanwhile the consequences of disrupted sysplex communication are too grave, including wait stating the entire sysplex. Too great a price to pay for whatever advantage you're reaching for. . . JO.Skip Robinson Southern California Edison Company Electric Dragon Team Paddler SHARE MVS Program Co-Manager 626-302-7535 Office 323-715-0595 Mobile jo.skip.robin...@sce.com From: Rob Schramm <rob.schr...@gmail.com> To: IBM-MAIN@LISTSERV.UA.EDU, Date: 10/09/2013 10:57 AM Subject: Re: Distance considerations fo a Parallel Sysplex with DB2 Data Sharing Sent by: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> The only comment is that the km or miles start to add up when a signal to a CF has to make the round trip there and back again. When looking at response times .. distance can make a difference. In general... the fact that this stuff can be done is just really cool. Rob Schramm On Oct 9, 2013 1:33 PM, "Scott Fagen" <scottfagen...@yahoo.com> wrote: > On Tue, 8 Oct 2013 17:38:02 +0300, Sheldon Davis wrote: > > >I was wondering what the maximum distance would be for a Parallel > Sysplex with DB2 Data Sharing on two BC12's. > > From http://www-03.ibm.com/systems/z/advantages/gdps/faqs.html > > How far apart can I spread my CF's? How far can I stretch my Parallel > Sysplex? > > ISC-3 links can be extended to 100 km without any RPQ. With RPQ 8P2263 > using qualified DWDM equipment, this can be extended to significantly > longer distances. Distances affect workload response times. More detail on > this is described in "GDPS/PPRC 100KM Test" at > http://www.ibm.com/common/ssi/fcgi-bin/ssialias?infotype=SA&subtype=WH&appname=STGE_ZS_ZS_USEN&htmlfid=ZSW03119USEN&attachment=ZSW03119USEN.PDF > > (mind any split). > > Scott Fagen > Chief Architect - Mainframe > CA Technologies > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
