As mentioned earlier, running the update workflow split into two parts - Caching and Resume after Cache.
The most time consuming part of the installation is the caching part. During caching, all the deployment units of the new software install have to be loaded into the host machine. Since the servers need to be updated one by one, the downtime is usually long.
Therefore, in order to reduce the downtime to a minimum time, we have introduced synchronous caching concurrently in all the servers, including CMS, Application Processing Servers, and Web-Tier.
The important aspect of this mechanism is that the machines can still be used by the users even during caching, as the final update can take place only after the running the resume after cache process.
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