So yer gonner migrate to Exchange? What do you need to consider?

Honeymoon Pictures 101 Well I’ve had the joy of doing a few of these so will share my experiences on how to get to the other side with minimum pain.  I’m just going to blog here about email ….. otherwise it would be far too long a post.  So here are some considerations:

  • Attachments are compressed by default in Domino.  Using Huffman compression in release 4 and 5 and if enabled LZ1 compression in Domino 6 and above.  This means that unless you have a third party compression tool doing similar in Exchange you will see an expansion factor of anything between 10 and 40% per attachment, my experience tells me to make sure for every 1 MB of data in Notes that there is 1.3 MB available in Exchange.
  • When you first migrate data the single instance does not work, so 1 email in Notes migrated to exchange = 1 email even if it has multiple recipients.  Single instance only operates for new emails once your users are running on Exchange.
  • What data are you going to migrate?  Email, calendar, to do, personal address books, archived emails, personal journals….
  • Where is the data?  If it is local to a user how do you manage the migration.
  • What tools and software do I need to deploy?
  • What level of co-existence do I need while both email environments are running?  none, email only, directory syncrhonisation, calendar and free time lookups – each adds complexity
  • When I’m migrating users are there any limitations which will cap the number of people I can move at once?  directory infrastructure, network bandwidth, number of migration stations, storage…..and many more

Well hopefully that will help a few people ensure they don’t miss huge chunks of work!!!!


  1. Well, another big issue is doclinks, especially if the migration will take a while or, as is often the case, your e-mail is migrating but your apps are staying in Notes. While Notes/Domino 6/6.5/7 purport to handle such doclinks (R5 simply destroyed them), the links created only seem to work about 1/3 of the time. Your choices are to use the Exchange Connector, which is essentially unsupported by Microsoft, although it is promised to be updated as part of Red Bull, or a third party product such as our CoexLinks.


  2. For me the biggest challenge has always been applications because they are the things with the longest life data. The challenge here is that customers have willingly moved email services over and left application where they are. They have done this, partly, to let Notes wither and die. Most customers are not bought into Notes being an application platform for the long run.

    Applications get revisited from time to time and it worries me when IBM start using the applications as a reason not to migrate. You can only rely on legacy renewals for so long.


  3. Ben and Graham you both make good points and in a future post I will consider applications. This is where the real pain is in terms of ensuring applications have no reliance on the Notes client. Without this users end up with a dual client experience and the pains of management of 2 environments come to the fore.


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