Scalability – MongoMK provides the ability to have multiple AEM instances share the same MongoDB instance. This shared all clustering approach enables horizontal scalability of AEM instances, adding additional AEM nodes as the load increases
Replication – MongoMK reduces the overhead of replication; it effectively delegates replication functionality to the MongoDB, which has mature model to maintain replica sets. Also the no. of MongoDB replicas and AEM instances can be scaled independently
Distributed Authoring teams – MongoMK helps when we have distributed authoring teams spread across geographies. Content changes does by all authors gets persisted to the same primary MongoDB instance and gets replicated to the secondary replica sets
Automated Recovery – MongoDB replica sets and automated failover helps with automated system recovery when the primary MongoDB instance goes down or in case of the whole data center failure; never the less TarMK also provides the option for setting up automated recovery
The choice of MongoMK or TarMK for authoring instance can be based on no. of AEM instances required in authoring environment, in line with Adobe recomendation. · If more than 1 active AEM instance is needed for Authoring environment – MongoMK · If the volume can be handled with 1 active AEM instance - TarMK
Code releases – When releasing code changes to production for Dotcom, we will have to release it to one data center, validate the release and then release it to the other data center. This is a mandatory requirement to ensure 24/7 availability. Such rolling release is well supported by TarMK. With MongoMK, code release gets replicated to all MongoDB replica’s making the isolated release to one data center difficult.
AEM Upgrades – Applying patches and release upgrades to AEM also requires rolling releases which is well supported by TarMK because of their shared nothing clustering approach
Horizontal scalability – Both TarMK and MongoMK supports horizontal scalability for publish instance. With TarMK, we can have a form of independent shared nothing AEM instances, which are kept in sync by replication.
The choice of MongoMK or TarMK for publish instance can be based on if the site supports user generated content or not.
· Site support user generated content – MongoMK
· Site does not support user generated content - TarMK
Thanks for the info guys. That's useful stuff. We decided to use MongoDb in authoring instance but still got doubts while posting this query on the forum. Now I got clear picture . I will keep post my experience with the MongoDB.