Before you run a virtual switch procedure, evaluate the applications you intend to test and make a plan so that testing can be as useful and the least disruptive to your environment as possible.
General planning: In general, do not leave an application group in virtual switch test status for an extended period of time. Have a plan for what needs to be tested, what resources you need, the people needed to perform application testing, and how long the test is expected to take. Consider the following:
Determine how much time you need for application setup and testing. If you have multiple applications to test, consider the total amount of time needed and total number of objects affected. It may be useful to test a limited number of applications during one run of the virtual switch procedure. You may not want to allow an application group to remain in its testing phase overnight. Or you may need to plan to run the procedure and test during off-peak production hours.
If a virtual switch is in progress for an extended time, both source and target nodes may be affected. Journal receivers can accumulate on the both source and target nodes of the affected data groups, and the queued work for apply sessions accumulate on the target node. On the target node, there are multiple considerations that affect the recovery phase, including, the quantity of accumulated production transactions that need to be applied, the number of changed target objects that need to be recovered, and manual cleanup.
All changes made to target node objects need to be reverted. The recovery phase of a virtual switch only reverts (recovers) changed target objects that are identified as eligible for replication by the configuration of the data groups affected by the virtual switch. MIMIX does not track or automatically revert any changes made to objects that are not eligible for replication by the affected data groups. This includes objects on test node as well as objects on other connected nodes or the cloud. Manual cleanup is required for these types of changes.
If you use row and column access control (RCAC) on a replicated file and change permissions or masks on the target node during virtual switch testing, be aware that virtual switch recovery will perform a full save/restore of the file.
Evaluate the application requirements: Consider the characteristics of the applications you intend to test. Some applications may not be suitable or may require additional effort to avoid affecting your larger environment.
Enable user profiles needed for the application on the target node at the beginning of virtual switch testing, before starting the application. Optionally, you can add this activity to step STRUSRAPPV with other customized application startup instructions.
In general, if the application needs certain user profiles, authorities, libraries, objects, or other items in order to run on the test node, consider adding configuration selection rules (data group entries) for those items so they are replicated to the target node.
Determine if the application needs communications access to the test node. This may need to be set up at the start of the testing phase.
If an application changes objects or creates data on other connected servers, the cloud, or in other applications, you may need to temporarily disable those capabilities to prevent generating data to those locations. If you cannot disable this activity, any changes outside of the designated test node may cause damaged objects and will require manual effort to revert. If disabling is not possible, the application may not be a good candidate for virtual switch testing.
If an application hard codes an IP address or system name, the application will not function properly and will not find the address or system when started on the virtual switch test node. These scenarios are issues in any switch and need to be resolved. You may need to work with the application provider to resolve them.
If your environment uses IP impersonation to change network names outside of MIMIX as part of your normal planned switch processing, carefully evaluate how applications interact with these changes to determine if virtual switching testing is viable for the affected applications.
Identify what actions you need to perform to start and end the application. Optionally, you can enable and customize steps STRUSRAPPV and ENDUSRAPPV with instructions to start and end the application on the test node as part of the virtual switch procedure.
Testing in Assure MIMIX IBM MQ environments: If your environment includes the Assure MIMIX IBM MQ feature and you perform a virtual switch of an application group that replicates an IBM MQ for IBM i queue manager, the AMQAJRN journal should not be allowed to change its journal receiver while in the application testing phase of the virtual switch. Do not intentionally change this journal receiver during virtual switch testing. If the receiver for this journal changes during virtual switch testing, a manual recovery process is required after the virtual switch procedure has completed. You will need to check for MQ-related topics in the Knowledgebase and may need to contact Support.