Please read this chapter before installing and deploying Kopano Archiver, in order to understand its terminology.
- Primary Server
The primary server is the server with the best performance and best I/O subsystem, that contains the mailboxes of the users holding the most recent data.
Although the term Primary Server suggests that there’s only one primary server, multiple primary servers can exist in a multi-server environment. In this document no distinction will be made between a single-server or multi-server environment unless explicitly stated.
- Archive Server
An archive server is the server that contains the archives for stores that reside on the primary server. An archive server is a Kopano server with the sole purpose of providing storage for one or more archive stores. In a multi-server environment this server will be just another node in the cluster. Unlike primary servers, there’s no need for a multi-server environment to have a multi-archive server setup.
An archive server is another kopano-server with the sole purpose of providing storage for one or more archive stores. In a multi-server environment this server will be just another node in the cluster.
Unlike primary servers, there’s no need for a multi-server environment to have multiple archive servers.
- Primary Store
The primary store is the store that resides on a primary server and on which a user normally works. Also known as Main Store
- Archive Store
The archive store is the store that resides on an archive server and which is used for storing archived messages from the primary store.
The archiver is the application to manage the archiving. Basically it can be used to attach primary stores to archive stores and execute archive runs. It can be installed on any Kopano server to connect to the primary or archive server using SSL authentication. It can also be used on a single server, using kopano-server‘s unix socket.
- Stubbed Message
A stubbed message is a message in the primary store that acts as a placeholder for the archived message. These messages occupy virtually no space in the primary store, but show a user that a message was once there. It also acts as an entry point to the archived copy of that message.
- Single Instances
Kopano uses single instance storage whenever possible in order to minimise storage requirements when data is stored more than once. Kopano Archiver makes use of this technology by remembering which instances it copied to an archive server and referencing that instance whenever possible.
- Attached/detached stores
An archive store is attached, when a data link is made with a primary store. Making such a link is called attaching a store, removing such a link detaching it. Detached stores are still available for reading.
- Hooked/unhooked stores
A hooked store is available for use as a primary or archive store. Unhooked stores are not available. From the perspective of a mail client or the Archiver they don’t exist. Such unhooked stores are also know as orphaned stores. Unhooked stores cannot be read from or written to. The process of making a store available for a user is called hooking, the reverse unhooking. An unhooked store may be removed.
- Archive Configuration
An archive store can be configured in two ways, one-for-one and one-for-many. This is not a system wide configuration and can be setup for each archive independently. This allows for hybrid systems where N users with small to medium stores can be placed on M archive stores (where M is significantly smaller than N) and users with big to huge stores can be placed on dedicated archive stores.
- One-for-One Configuration
In a one-for-one configuration one archive store is attached to one primary store. The advantage of this configuration is that it’s faster as the archive store itself is kept smaller. The disadvantage is that for each user an additional non-active user needs to be created (since there’s a one-to-one mapping between stores and users in Kopano).
- One-for-Many Configuration
In a one-for-many configuration one archive store is attached to multiple primary stores. For each attached primary store a folder is created in the archive store that will act as the root of the archive for that particular primary store. The advantage of this configuration is that less additional non-active users are required. The disadvantage is that the archive will become slower if the total amount of archived data in it grows.