z/VM allows you to connect multiple virtual machines with virtual CTCAs. -- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 עַם יִשְׂרָאֵל חַי נֵ֣צַח יִשְׂרָאֵ֔ל לֹ֥א יְשַׁקֵּ֖ר
________________________________________ From: IBM Mainframe Discussion List <[email protected]> on behalf of Mike Schwab <[email protected]> Sent: Friday, June 21, 2024 11:49 AM To: [email protected] Subject: Re: GRS in MONOPLEX without physical CTCs ? Can z/VM do this? Costs? On Fri, Jun 21, 2024 at 8:45 AM MANCINI Frédéric (80) <[email protected]> wrote: > > Actually, we do share a few DASD devices between our lpars. > > Thanks to all the replies, I understand better now what we must do in > order to implement a fully functional GRS without buying an external > coupling facility. > > I understand that we can leave our lpars in MONOPLEX mode and use GRS > managed CTCs, possibly on a ring architecture in order to minimize the > hardware connections. > > Using virtual CTCs without interconnecting the MONOPLEX lpars doesn't > seem to make sense for resource serialization. > > Am I right ? > > ------------------------------------------------------------------------ > *De :* Tom Marchant [mailto:[email protected]] > *Envoyé :* vendredi 21 juin 2024 à 15:30 > *Pour :* [email protected] > *Objet :* GRS in MONOPLEX without physical CTCs ? > > > The OP hasn't said whether or not any DASD is shared. > > > > If there is a need to share PDSE, it is only supported within a Sysplex. > > MIM is not sufficient > > > > -- > > Tom Marchant > > > > On Fri, 21 Jun 2024 13:49:29 +0200, Radoslaw Skorupka > > <[email protected]> wrote: > > > >> To complement: > >> Parallel Sysplex - a CF is required, which mean sysplex links (emulated, > >> free - for PS within single CPC). GRS is STAR mode is possible and > >> strongly suggested. (GRSplex is required, the mode is suggested). > >> > >> Base Sysplex - CTC links required. In the old days also sysplex timer. > >> Now it can be sysplex link to provide time synchronization for STP > >> (Server Time Protocol). The GRS is mandatory and it's configuration is > >> RING, which is not the best from performance point of view. For base > >> sysplex within single CPC there are no STP-only links, but CTC over > >> FICON is required. Note: the FICON can be shared, that means used for > >> other purposes. > >> > >> Monoplex. GRSplex is still possible (unless something changed) and it is > >> RING topology with drawbacks mentioned above. Of course multiple > >> monoplex LPARs may share DASD without GRSplex, but again it is not > >> seamless - at least PDSE sharing is almost impossible. > >> > >> ...and there is CA-MIM family of products. :-) > >> > >> > >> -- > >> Radoslaw Skorupka > >> Lodz, Poland > >> > >> > >> > >> > >> W dniu 21.06.2024 o 08:41, Brian Westerman pisze: > >>> You can just use extra FICON interfaces as FCTC's. IBM refers to that > >>> method as a baby sysplex. It allows you to have GRS in ring mode. TO > >>> have star mode you need CF's. > >>> > >>> If you have multiple LPARs and you share dasd, then you need either CF's > >>> (expensive) or Ficon CTCs (pretty cheap). The setup is very simple. > >>> CF's are much faster but ficon CTC's easily handle 3,4 or 5 lpars without > >>> any issues at all. > >>> > >>> Brian > >>> > >>> ---------------------------------------------------------------------- > >>> For IBM-MAIN subscribe / signoff / archive access instructions, > >>> send email to [email protected] with the message: INFO IBM-MAIN > >> ---------------------------------------------------------------------- > >> For IBM-MAIN subscribe / signoff / archive access instructions, > >> send email to [email protected] with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to [email protected] with the message: INFO IBM-MAIN > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN -- Mike A Schwab, Springfield IL USA Where do Forest Rangers go to get away from it all? ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
