How to set up multiple DRAS tasks for load balancing and DR contingencies?

Document ID : KB000014515
Last Modified Date : 14/02/2018
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Introduction:

How to set up multiple DRAS tasks for load balancing and DR contingencies?

Question:

When you have multiple LPARs using CCI and DRAS tasks to support Web Viewer -

What if the primary LPAR is lost or needs to be shut down?

With automatic DRAS load balancing and CA OM Web Viewer, will it load balance the users among the available DRAS servers?

Environment:
Multiple DRAS and CCI taskes across several LPARs
Answer:

Basically, we're talking asking about 1: load balancing and 2: DR/contingency (fail-over) with regard to DRAS. 

1: Web Viewer currently supports load-balancing at the repository level. Users, upon repository selection, are randomly connected to one of the associated DRAS repositories (if more than one is assigned). If a particular DRAS repository is not available, Web Viewer automatically tries a different one. 
 
2: Although DRAS can load balance/fail-over at the repository level, there is no such provision when the defined primary LPAR fails, in that it cannot balance/fail-over if the target CCI system or the primary (license/web login) DRAS task are down (or their LPAR is down). These are set in the configuration files (CCIClient.properties and WVProfile.properties) for each Web Viewer instance. 
Note: Some customers have implemented DR procedures to quickly (hopefully) switch to a functioning LPAR. Basically, they swap the configuration files (CCIClient.properties and WVProfile.properties) to point to a different LPAR/DRAS task & recycle the web server. They then reverse the procedure after they recover from the disaster. 

Additional Information:

Can I use the same Server ID if the task runs on a different LPAR?", the answer is YES. DRAS tasks on different LPARs may use the same ServerID (since the ENF ID is unique). You can see this in repository definitions when you discover DRAS tasks in the format LPAR:DRASServr:Repository. 
Note: When DRAS starts, it "registers" itself with ENF by ServerID (actual "DRAS<ServerID>""). If it's already registered to that ENF, the task will immediately end with a message stating already in use.