Moving mailbox to another database, whitespace

Question

Hello,
Could someone please advise me,
If i move mailbox to another database, will it take database's whitespace or will it increase size of database?
Thank you.

Answer 1

Hi @escpoar ,

If i move mailbox to another database, will it take database's whitespace or will it increase size of database?

Let's say a mailbox is moved to db1, db1's whitespace will be used in priority, if the whitespace is not enough, the size of the database will be increased.

Below are the test steps I used in my lab, hopefully you can find it helpful:

1. Dismount db1, run ESEUTIL /MS to check the available whitespace in the database by referring to this blog.
   
2. Remount db1, move a user mailbox from another database to db1.
3. Dismount db1 again and rerun ESEUTIL /MS against it, from the output we can see that the whitespace is used:
   

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Answer 2

Example of mailbox database size and available new mailbox (white) space

Database DB01 is 90 GB in total size. Only 70 GB is in use, and 20 GB is available (white) space. We moved mailboxes to another database, and users are deleting data from their mailboxes. A total of 20 GB is free, that’s the available new mailbox (white space).

Within time mailboxes are created, or mailboxes will grow in size on database DB01. It means that the database size will get bigger. It will first use the remaining 20 GB of available new mailbox (white) space. In our example, 10 GB is in use. The total database size remains at 90 GB, in which 80 GB is in use by the mailboxes, and 10 GB is the available mailbox space.

When there is no available white space left, it will take the available space of the volume disk D:. The database will grow in size, and the disk space on the volume will grow together.

If we remove mailboxes or move mailboxes to another mailbox database, the white space will be available again. We will start all over again. The database will grow in size, and it will first use the available new mailbox (white) space.