We have recently been made aware that additional SQL Licensing is not required to have a mirrored/replicated contingency server provided that the server is dedicated as Contingency and not in use for other processes.
With this is mind can anyone please advise if mirroring/replication is possible with Clarity?
Mirroring of SQL Server is not supported with Clarity PPM.In fact we have seen that using mirroring leads to issues that customers were able to correct by removing it. I would recommend you use other different options to improve the data protection and availability of your SQL Server database.
I hope this helps.
Nika HadzhikidiCA TechnologiesPrincipal Support Engineer
Thank you Nika.
Ok so mirrroring is definitely out.
Can replication be used? e.g. transactional, merge or snapshot replication?
Unfortunately SQL Server replication is not supported either. Please check with your DBA for any other alternatives you may use with your database server.
SQL Server is supported only for a maximum of 5000 Clarity PPM users, so I believe this is the reason that those options that would be more of use for larger systems were not added to support. Please feel free to raise an idea here in the Communities if you feel this is a feature that should be added to Supported list.
The problem - at least with most of these offerings - is that they need to modify the schema in ways to ensure they have some kind of referenceable 'key' field for managing the syncing up between the two servers, and that typically involves adding extra columns and constraints that then cause parts of the application and upgrade to be broken when it runs SQL to modify the structure of the schema objects (views, indexes, tables).
Should there be a truly transparent mirroring/replication offering that doesn't cause or require changes to the schema (especially on some tables with no primary keys - for which we have some - as this is where those technologies are most likely to modify the schema if not everywhere else too anyway), then it may well 'work' even though it won't strictly be something we have that is supported.
The things I have been describing though are real examples where these configurations and the software driving them have caused PPM to break and are not just hypothetical. But something that just uses the data from transaction log files and makes zero changes to the PPM schema might work.
One other issue to consider now with the DWH schema is that sometimes transaction logging is intentionally disabled for some operations (from within the code), and that would likely violate replication/mirroring technologies from working correctly.
Thank you Nika and Nick. Very insightful information as always