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
