Cloning environments in-flight
z/OS volumes can be copied fast and efficiently, even faster with hardware enhanced facilities like Flashcopy, Snapshot, Timefinder, ShadowImage, and others. With these facilities point-in-time volume copies can be provided nearly instantaneously. This means that entire application landscapes can be duplicated within seconds. However, it is still required to rename and re-catalog the datasets and to adapt DB2 and, if involved IMS, to the new naming rules. Cloning tools automate the whole cloning process, they generate the jobs to copy the volumes, to rename and to re-catalog the datasets, to adapt DB2 and IMS. Clones will automatically recover when started the first time. The process is similar to the recovery process after a power failure and is fully under the control of the respective DBMS, DB2 or IMS. Naturally, in order to facilitate recovery and to keep the recovery time within reason, it is advisable to abandon heavy and long running update transactions as well as utility executions whilst the volume copies are made.
To clone a living system hence requires
- a DASD copy facility that is able to make consistent copies over the entire set of involved volumes, most hardware vendors offer a solution for this
- a cloning tool that utilizes the point-in-time copy facility to make the clone,
that the level of activities is kept low during the copy (split, flash, etc.) in order to enable the clone to recover in decent time
- that the level of activities is kept low during the copy (split, flash, etc.) in order to enable the clone to recover in decent time