I don't have nearly 1TB, but on a machine with 2.0 GB in store (I do have compression enabled as well), and my db directory is 447 MB.
I suppose it all depends on what you have for metadata (number of folders and accounts and such). The metadata for one user with one folder and 10 GB of mail will probably take considerably less space than 1,000 users with 100 folders and 10 MB of mail each. |