The Aggregating Content Store is specifically designed to combine multiple content stores into a single virtual store. It designates one store as the primary, which handles all read and write operations for new content. The remaining stores are configured as secondary, read-only stores. This architecture is commonly used for content migration scenarios, allowing access to legacy content in read-only archives while all new content is directed to the primary store.

A. File content store: This is the default, single-store implementation. It does not have the built-in capability to aggregate multiple stores or define primary/secondary read-write/read-only roles.

B. Selector Content Store: This store routes new content to one of several underlying stores based on defined rules (e.g., content type or properties), but it doesn't create a primary/secondary read-only structure.

C. Caching content store: This store provides a local cache for a remote backing store to improve performance in distributed environments. It is not designed to aggregate multiple read-only secondary stores.

1. Alfresco Content Services 7.4 Documentation, "Types of content stores":

Aggregating content store: "The Aggregating content store is a content store that aggregates a set of stores. It is a primary store for read and write, and a set of secondary stores for read only."

Selector content store: "The Selector content store provides a mechanism to select a content store to use from a set of stores, based on a content model property."

File content store: "The File content store is the default content store implementation."

Reference Location: Alfresco Documentation > Alfresco Content Services 7.4 > Administering > Repositories > Content stores > Types of content stores.

2. Alfresco Content Services 7.4 Documentation, "Configuring the Aggregating content store":

"The Aggregating content store is a content store that aggregates a set of stores. The first store in the list is the primary store. The primary store is the store that all new content is written to. The other stores are secondary stores and are read-only."

Reference Location: Alfresco Documentation > Alfresco Content Services 7.4 > Administering > Repositories > Content stores > Configuring content stores > Configuring the Aggregating content store.