Migrate mailboxes and archives imported
I am performing a project, where mailboxes from environment A are migrated to environment B.
Environment A is Exchange 2007, with EMC MailXtender, and Environment B is Exchange 2007 with EV90SP2. items in Environment A are archived in EMC, and have EMC shortcuts (messageclass IPM.Note.EXShortcut).
The admin of environment A is exporting archived items per user into PST's, which are imported in (EV) user-archives in environment B (without creating shortcuts, and in a specific folder). The admin of environment A also restores the EMC archives back into the mailboxes, to remove the existing EMC shortcuts. After this excercise, the mailbox from Environment A is moved to Environment B where the moved mailbox is being archived. This means that the mailbox contains items that are already in the archive.
Obviously. this means that in the archive (when EV archiving in Environment B runs), there will be double items in the archive.
Will this (however) mean that when the items are archived, due to SIS, the items are not stored twice, or will they get archived twice anyway?
I am not yet able to determine this, as we have not yet started migrating mailboxes from Environment A.
I am trying to convince the admin in A that there is no point to restore these items, but if that fails, what can be the effect on the storage for EV?