We updated the Exchange 2007 Mailbox Storage Requirements Calculator (again)…

…that we blogged about here.

What’s new, you ask?  Quite a bit… we’ve been busy.

  1. We have changed the way you input transaction log growth.  In the previous versions you had to enter how many transactions (in gigabytes) you expected the server to generate in a day.  Many customers found that was hard to quantify and thus left the default value.  The problem there is the default value was specific to the example configuration provided.  Thus changing any of the values resulted in truth a different transaction log generation profile.  Now what we do is base transaction log generation growth on the message profile.  So a heavy message profile mailbox will generate 28 transaction logs per day.  This provides us and you a way to accurately predict the database and log capacity requirements based on the message profile.
  2. We incorporated the effects of using online mode clients in terms of the database read I/O operations.  For more information on the effects online mode clients can have against the mailbox server read I/O operations, see the Storage Validation blog article.
  3. We added a new tab to the calculator.  We now have a Backup Requirements tab that outlines the backup scheme based on the backup methodology and frequency chosen.
  4. We made a few bug fixes in a few calculations (e.g. we were adding in the I/O Overhead Factor twice in the case of transaction log I/O transfers).
  5. General formatting changes to ensure that users would understand the requirements around per replica, per node, etc.

We have attached the new version of the calculator to the original post. Let us know if any questions/suggestions!

Ross Smith IV

Comments (17)
  1. Brian says:

    Can we have a link to the new storage calculator?

  2. Exchange says:


    Please see the original post, in other words this:


    Rather than have different versions floating in different posts, I have removed the older version from the original post and put a new version (v3) in.

  3. Del says:

    Great, v2 help’s us a ton to move forward with SAN storage planning.  some quick feedback on v3

    1). We see now when using LCR, LUN calculations are easier to understand.  

    2). When using "Online Mode", Require DB and Logs IOPS and IOPS/Profile /Mailbox seems to have a calculation error.

  4. Hi Del,

    What error are you getting when you choose Online Mode?


  5. Jeff25 says:

    You you change the Outlook Mode to Online Mode the IOPS Profile/Mailbox, Required Database IOPS, and Required Log IOPS displays an error which reads, "The formula contains unrecognized text."

  6. Hey Jeff/Del,

    I figured out the issue.  You are using Excel 2003 aren’t you?  By default certain formulas are not enabled unless you load the Analysis Toolpack.  For instance, I make use of MROUND function in this version of the calculator and that is only loaded in 2003 with the Analysis Toolpack.

    To load the Analysis Toolpack:

    1. On the Tools menu, click Add-Ins.

    2. In the Add-Ins available box, select the check box next to Analysis Toolpak, and then click OK.

    3. If you see a message that tells you the Analysis Toolpak is not currently installed on your computer, click Yes to install it.

    4. Click Tools on the menu bar. When you load the Analysis Toolpak, the Data Analysis command is added to the Tools menu.


  7. All,

    We replaced v7.7 with v7.8 which adds a note regarding the need for the Analysis Toolpack if using Excel 2003 and we fixed a compatibility conditional formatting issue on the Backup Requirements tab.

    It’s attached on the original storage calculator blog linked earlier in this blog posting.


  8. Anonymous says:

    Disk Performance Testing with Jetstress 2007 Installing Exchange 2007 into a Small Business Server 2003

  9. Kevin Belton says:

    Thanks for the knowledge on the Analysis Toolpack!  We have 2000 users and 2003 users, this will be needed!

  10. Brian says:


    Do you know when we might start to see Exchange 2007 ESRP solutions? All the ESRP solutions today are designed for Exchange 2003. Are we waiting on Microsoft to finalize the 2007 ESRP program or are we waiting on vendors to test their solutions?



  11. Hi Brian,

    That is a great question.  Many storage vendors are currently in the testing phase now, and a few solutions have been submitted.  We expect the results of thos submissions to be posted within the next month.


  12. SLundahl says:

    I need to build a Client Access Server and am having difficulty determining what storage needs are specific to that role.  I’ve found information on memory and processor requirements but not storage.  How do I determine disk requirements for this role?

  13. Sean says:

    In the storage calculator, can someone validate and explain why having a dedicated restore LUN reduces the size of the database disk store? For example:

    1000 Mailboxes

    100MB Size

    No to Cont. Replication

    and then depending on Yes or No to dedicated restore lun you have either:


    Database Disk 270GB

    Total Log 120GB

    Restore LUN 392GB

    Total = 782GB

    or NO to dedicated restore lun

    Database Disk 522GB

    Total Log 277GB

    Restore LUN = 0

    Total = 799GB

    so, disabling dedicated restore increases total storage needed per server?  

  14. Slundahl,

    There are very little requirements in terms of storage for a dedicated client access server.  The OS, Page File, and Exchange binaries are about it.  Other than that not much is stored on disk.


  15. Hey Sean,

    If you have a dedicated restore LUN, then you do not need to provision extra space on the SG DB and SG Log LUNs for restoration or offline maintenance practices.

    If you do not have a restore LUN then you have to provision extra space on each SG DB and SG Log LUNs for restoration or offline maintenance practices.

    Hope this helps,


  16. choijames says:

    With the storage calculator, can you kindly explain the following questions, please?

    (1) Why the CCR (& LCR) option’s LUN requirement layout is different from ‘none’ option but the total size of db, log & LUN are same?

    (1.1) Does it mean that I need to double those size for CCR/LCR? Unless the calculator is wrong, it seems to suggest to double those sizes.

    (2) Why the LUN DB numbers different between CCR and ‘None’ options?

    (3) Is this calculator assume that I need to calculate per server? Or can I enter, for discussion sake, 60,000 users and expect the calculation results within acceptable range?

    Thanks for your answers or comments in anticipation.



  17. Hi JC,

    1.  The number of storage groups changes when you remove CCR/LCR configurations, because without continuous replication, the recommended maximum mailbox size changes from 200GB to 100GB.  This of course is not a hard limit, but a recommendation based on general recovery times.  In other words, without a secondary copy you must resort to a backup to recover; the larger the database size, the larger the restore window.

    1.1.  Yes you need to double.  For example, on the Storage Requirements tab, notice cell A66.  It states "Total Database Disk Space Required (GB) / Replica" which means that this is the total disk space required for each replica.  So when continuous replication is enabled, you will need to double that number (since each replica will require disk space).

    2.  See my answer to #1.  To determine how many databases to recommend, it’s a function of mailbox size, number of mailboxes, and max database size.

    3.  This tool is used to calculate per server.

    Hope this helps,


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