DAOS – it’s not just for mail!

Most of the readers of this blog will be aware of DAOS by now – the new Domino Attachment and Object Service implemented in Domino 8.5.0 and above.  One whitepaper describes DAOS as:

DAOS exampleWith 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.

It is easy to see how this new service can make a massive difference to mail server disk use – each mail attachment is only saved once rather than in every mail database it is added to.  

In our real world experience of implementing DAOS for customers, it typically saves 30-50% of disk space on a medium-to-large Domino mail server.  In addition, of the disk storage still used by mail, approximately half is shifted from the Domino databases themselves (the NSFs) into the DAOS store (effectively a flat filesystem containing encrypted and renamed copies of the attachments).  That means that the actual size of the Domino data mail directory has been reduced by 65-75% – say from 1TB to 300GB, adding knock on benefits such as significantly faster backup/restore times, reduced load due to full-text indexing and view updates and much lower disk I/O bandwidth requirements.  DAOS really is a no-brainer for any mail-server being upgraded or migrated to Domino 8.5! (Please note that this doesn’t indicate that the process is without its gotchas or areas requiring careful consideration – always consider calling in your trusted Lotus partner to offer assistance and best practices planning and design).

However, the reason for this post is to reiterate that DAOS is not just for using on mail servers – it works with attachments in any Domino server-based NSF database.  Therefore, if you have large Domino/Notes applications that include attachments, DAOS can make a significant impact on the size of the database(s) and therefore on the performance of the application and the server(s) they run on.  

We’ve just seen a great example of this at an insurance company, where they have an customer and claims management application that has recently been upgraded from Domino 6.5 to 8.5.  Storing many images and scanned documents relating to traffic accidents, building damage etc, this application had one single database that was 32GB in size (after a regular compact task had been completed).

After upgrading the servers hosting the database to Domino 8.5, enabling document and design compression, upgrading to the latest ODS and enabling DAOS, this single NSF database has shrunk to 7GB in size.  A 78% improvement!  You can imagine what a massive impact this will have on the vitality of the application and the server hosting it.  Multiply that by the many distributed servers running this app, and the customer has realised a significant improvement from completing the upgrade.

So, if you’re currently considering whether you should upgrade to Domino 8.5, and in turn whether to enable DAOS on all your servers, hopefully this will convince you to complete the upgrade sooner rather than later.

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