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Guidelines on how to move hundreds of mailbox to a new store safely.

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  • Guidelines on how to move hundreds of mailbox to a new store safely.

    hi guys,

    My team and i are planning to move about 500+ mailboxes to a new store(same machine) safely. We're using Exchange 2003 Ent and Server 2003 Ent.

    Currently we have a whooping 780GB edb size and 160gb stm. To some up all the physical mailbox size on the 500+ mailboxes(via ESM>mailbox store>mailboxes) i only get a total of 140GB.

    Question is what will be the size of the new store once we move all the 500+ mailboxes on it? is it the same 780GB? or the actual physical size of the mailboxes 140GB?

    And one thing, does moving mailboxes in large volumes wont cause database errors/corruptions?

    Last edited by sp37zn4z; 17th February 2012, 08:33.

  • #2
    Re: Guidelines on how to move hundreds of mailbox to a new store safely.

    If I remember correctly the server based deleted items will not be moved in Exchange 2003 while moving mailboxes to another store, so the size should be around that 140GB you are now seeing.

    But since you are using Exchange Enterprise the question is why you are not using more than one database in the first place. This would ensure that the file size will never get that high as your current one nor the 140GB.

    Now to your second question if your Exchange and the used storage is working appropriate there should not occur any corruption or inconsistency while moving mailboxes.
    But you can alyways move in chunks like 10, 50 or 100 users.

    If you move many users with big mailboxes at the same time make sure your transaction log partition is big enough or that you have circular logging enabled.


    • #3
      Re: Guidelines on how to move hundreds of mailbox to a new store safely.

      Adding up the list of what you see in ESM will never come close to the size of the store. This is because ESM only shows you the size of the mailboxes using data from one of the two databases.

      It is impossible to predict the size of the store that you will get after moving the content. The closest you can get is probably the size of the store minus the white space reported by event ID 1221. Corrupted items and content in deleted item retention will also make a difference.

      Do you only have one spare database on the server? That database size is well over what I would be comfortable with and would prefer to see it split in to two or even three databases. On Enterprise edition you have Four Storage Groups with Four databases in capacity, so you can split that database in to much smaller databases (the usual number that is preferred is around 200gb).

      I have never seen database corruption with doing large mailbox moves. It will not be very fast though unless you have all the databases and transaction logs on separate arrays.

      Simon Butler
      Exchange MVP

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