What are mailbox stubs and what should I do with them?
Email stubs (or pointers) are a confusing concept, but because the concept is so important when migrating the on premise email to Office 365, it’s a good idea to look at them in a little more detail. The most important (and highly marketed) feature of email archiving solutions was to automatically remove email and attachments from Exchange and move them to the archive to reduce Exchange storage requirements and supposedly increase server performance. The user was presented with a link in the original email, which they would “click” to access the email and attachment in the archive (if one existed). The purpose of stubbing was to keep mailbox capacity in check. In most cases it worked very well. Using stubbing, Exchange Administrators could set a mailbox “cap” and solve the problem of Exchange storage growth... good for Exchange, but you can imagine how the archive capacity grew exponentially. Depending on the length of service for your email archive, the total size of the archive could exceed Exchange by 10 times (or more).
Stubs and email migrations
Before you migrate your Exchange email to Office 365, you must do something about the stubs. One choice is to simply delete them, but this will cause ongoing problems including severe user backlash. A second choice is to use the native “replace stub” command in the archive solution, if one exists. The trouble with this method is that it can potentially cause un-repairable damage to email. In addition, it is likely impossible to re-hydrate all the stubs in-place in Exchange server, due to lack of storage capacity.
The stub management best practice is to re-hydrate all the stubs “in-flight” as they migrate from Exchange to Office 365. Archive360's Archive2Anywhere performs a proprietary integrated email Stub or Shortcut Management process that involves four sub-processes; finding stubs, rehydrating stubs, stub redirection, and stub deletion.
All of these capabilities are critical for reteaining compliance and legal defensibility. Companies that have relied on improper methods of stub management during migration have caused irreparable damage to their email and raised their risk factor dramatically.