Daniel Nashed's Blog

Leveraging DAOS for storage optimization and backup

Domino DAOS (Domino Attachment and Object Service) was introduced in HCL Domino 8.5, released in 2008.
It replaced the old approach "Single Copy Object Store which never really worked well.

In contrast DAOS is much simpler and robost approach where the server gernerates an unique hash for each backend object behind an attachment and creates a NLO file (Notes Large Object) storged outside the .nsf file.
But still not everyone is lerveraging DAOS -- It can have also have great benefit on backup.

Benefits:

• Deduplication can save ~ 30% dpending how attachments are spead
  
  
• Up to 60% - 70% of storage could be either deduplicated or storged in DAOS which leaves the .nsf file to like 30% - 40% of the original .nsf file.
  
  
• .nsf requires high perfomance disks and generates many small I/O operations
  In contrast DAOS uses larger I/O operations and works well on standard disks -- which already is great optimization
  
  
• The smaller .nsf files are also easier to maintain. DBMT and other operations are working much faster on smaller databases  
  
  
• DAOS .nlo files are written once and a reference count is maitained. in daoscat.nsf.
  In contrast to .nsf this makes .nlo files the perfect ingremental backup candiate -- which doesn't require a Domino aware backup
  
  
• This means you can focus on the way smaller .nsf files for online backup

Consider DAOS also for backup purposes

If you never used DAOS, you should really consider looking into it and review your backup strategy.
When encryption is disabled the DAOS store is also a candidate for cross server deduplication.
You could point DAOS for multiple servers to a deduplicating storage provider to gain more storage benefits and central DAOS backup.


DAOS Tune

How to find out how DAOS would look like for your server?

The new DAOS Tune replaces the earlier DAOS Estimator.
It is completely rewritten, much faster and provides more details.
DAOS Tune can run without specifying and parmeters, but also supports more detailed analysis options.

Here is a sample scan for the DNUG production server -- which is not fully representative but shows the principle.

In our case we would only gain 15% deduplication.
But you can see that the remaining space in NSF is around 50% -- even on this small server..

When analayzine our DNUG server I noticed DAOS Tune wasn't yet in the container image.
You can now automatically add it to the container image via -daostune build option.

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