IBM® Lotus Domino attachment and object service (DAOS)

The IBM® Lotus® Domino® attachment and object service (DAOS) in release 8.5 reduces the total cost of ownership and helps customers with green computing practices by storing all file attachments in a separate repository on the server and retrieving them by reference. Read more to plan, set up, configure, and manage Lotus Notes® large objects.



With the release of version 8.5, IBM Lotus Domino server employs the Domino attachment and object service to save significant space at the file level by sharing data identified as identical between databases (applications) on the same server. Document attachments are the first components to use the DAOS feature in Lotus Domino.

In databases that use DAOS, Lotus Domino no longer saves a separate and complete copy of every document attachment. Instead, the server saves a reference to each attached file in an internal repository, and it refers to the same file from multiple documents in one or more databases on the same server. When an attached file is large and a message containing it is broadcast to thousands of users, creating a separate copy of the message for each recipient could require several gigabytes of disk space. Multiple copies of the same attachment often also proliferated in mail threads with multiple replies. With DAOS enabled, disk space usage is substantially reduced.

Use of an attachment object store is optional, and it involves considerable planning before you can implement it in Lotus Domino.

You can mark databases on a Lotus Domino server for participation in attachment consolidation by enabling consolidation on the DAOS tab in the Server document, and by ensuring that every database that you want to include in consolidation has the "Use Domino Attachment and Object Service" advanced database property selected. DAOS also requires transaction logging to be enabled. DAOS stores a single copy of each attachment in a central mapped repository. After you enable attachment consolidation on a server, all databases on the server that are included in consolidation use the repository to store attachments.

When attachment consolidation is enabled and a user saves an attachment, the body stored in the document contains a reference, sometimes called a ticket, to the attachment, which identifies the attachment in the repository. Consolidation occurs immediately; you do not have to wait for a task to run before disk space savings occur in the size of documents with attachments.