|
|
|
The CTCONLY method is a control file located in virtual storage (VCF) in a master CA MIM address space and passed from the master to client systems through CTC devices.
With the CTCONLY communication method, the MIMplex can consist of sysplexed and non-sysplexed images. No shared DASD or coupling facility structure control file is required.
The CTCONLY communication method passes a virtual control file (VCF) on demand from a selected master system to client systems. The VCF is passed between systems using 3088 or ESCON CTC devices allocated to the CA MIM address space on each system. The CTC devices to be used by CA MIM are identified on CTCPATH statements in the MIMINIT member.
Conceptually, a CTC device connects an I/O address on one processor to an I/O address on another processor. VCF data that is sent from one side is received on the other side, so every transmission consists of two operations, an outbound write operation from one side, and an inbound read operation on the other side. Data may be transmitted in either direction over a CTC path, but it travels only in one direction at any one moment.
We recommend that sites using the CTCONLY communication method be configured symmetrically (that is, every system in the MIMplex should have a CTC path available to every other system), so that multiple systems are eligible as master systems. This redundancy provides the best recovery options.
| Copyright © 2012 CA. All rights reserved. | Tell Technical Publications how we can improve this information |