Hi Emily, Content is stored in Oak in two different configurable storage services. This is a bit of an oversimplification, but basically the structure of content repository - the content tree, nodes, properties, etc. - is stored in a Node Store [0] and the binary content is stored in a Blob Store [1] (you'll also sometimes see the term "data store"). Oak manages all of this transparently to external clients.
Oak clustering is therefore achieved by configuring Oak instances to use clusterable storage services underneath [2]. For the node store, an implementation of a DocumentNodeStore [3] is needed; one such implementation uses MongoDB [4]. For the blob store, an implementation of a SharedDataStore is needed. For example, both the SharedS3DataStore and AzureDataStore implementations can be used as a data store for an Oak cluster. So, assume you were using MongoDB and S3. Setting up an Oak cluster then merely means that you have more than one Oak instance, each of which is configured to use the MongoDB cluster as the node store, and S3 as the data store. [0] - https://github.com/apache/jackrabbit-oak/blob/trunk/oak-doc/src/site/markdown/nodestore/overview.md [1] - https://github.com/apache/jackrabbit-oak/blob/trunk/oak-doc/src/site/markdown/plugins/blobstore.md [2] - https://github.com/apache/jackrabbit-oak/blob/trunk/oak-doc/src/site/markdown/clustering.md [3] - https://github.com/apache/jackrabbit-oak/blob/trunk/oak-doc/src/site/markdown/nodestore/documentmk.md [4] - https://github.com/apache/jackrabbit-oak/blob/trunk/oak-doc/src/site/markdown/nodestore/document/mongo-document-store.md Does that help? -MR On Thu, Dec 13, 2018 at 5:52 PM ems eril <[email protected]> wrote: > Hi Team , > > Im really interested in understanding how oak cluster works and how do > cluster nodes sync up . These are some of the questions I have > > 1) How does the nodes sync > 2) What is the mongo role > 3) How does indexes in cluster work and sync up > 4) What is the distributed model master/slave multi master > 5) What is co-ordinated by the master node > 6) How is master node elected > > One use case I have is to be able to leverage a oak cluster to be able > to upload images/videos and have a consumer on one of the nodes process it > in a distributed way . I like to try my best to avoid unnecessary read > checks if possible . > > Thanks > > Emily >
