When building HA setups it is essential to be able to replicate the database and ideal to have master<->master replication so that updates can be processed by multiple front ends concurrently regardless of whether or not the "master" database is online / contactable.
In order for this to work some subtle changes are required to the WHMCS database .. both storage formats need to be looked at, and also a move away from "auto increment" and towards the use of UUID keys instead.
Whilst this is a "specialist" requirement for the "larger" providers, it could also be useful for all WHMCS providers to enable real time backups of their databases in case of any failure / outage / etc.
We already have an HA setup for WHMCS however the weak link in this setup is the current database structure. The changes required would be "subtle" and ideally implemented in a major version change such as 6->7
We would be happy to work with WHMCS developers to implement the necessary changes
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