Data Protection Manager 2007 Storage Calculator

In order to assist customers in designing their storage layout for Data Protection Manager 2007, we have put together a calculator that focuses on outlining the storage capacity requirements based on a set of input factors.

For the first release, the calculator focuses on Exchange 2007 backup scenarios only.  Future releases may include other technologies.

The calculator uses all the recommendations outlined in

·         Protecting Exchange Server with DPM 2007 White Paper –

·         Exchange 2007 Planning Storage Configurations –

·         Exchange 2007 Mailbox Storage Calculator –

·         DPM Blog –

The calculator does not make any recommendations toward storage design (RAID parity, number of disks, etc) as the storage design is largely dependent on the type of storage array being utilized.

The calculator is broken out into the following sections (worksheets):

·         Input

·         DPM ExBackup Requirements

Important: The data points provided in the calculator are an example configuration.  As such any data points entered into the Input worksheet are specific to that particular configuration and do not apply for other configurations.  Please ensure you are using the correct data points for your design.


This section is where you enter in all the relevant information regarding your design, so that the calculator can generate what you need in order to achieve your design.

Note: There are many input factors that need to be accounted for before you can design your solution. Each input factor is briefly listed below; there are additional notes within the calculator that explain them in more detail.




 Exchange Server Configuration

1.       How many Exchange mailbox servers are there? Enter the number of Exchange mailbox servers that will be backed up by DPM.

2.       How many databases will each Exchange server have?  Enter the number of databases each Exchange server will have.  This value can be obtained from the Exchange 2007 Mailbox Storage Requirements Calculator’s Storage Requirements tab “Database Configuration” table.

3.       What is the LUN Design Architecture?  Enter the LUN Design architecture each Exchange mailbox server will use.  This can be obtained from the Exchange 2007 Mailbox Storage Requirements Calculator’s LUN Requirements tab “LUN Design” table.

4.       What is the total database disk space required?  Enter in the total amount of disk that will be used by each Exchange mailbox server.  This can be obtained from the Exchange 2007 Mailbox Storage Requirements Calculator’s Storage Requirements tab “Disk Space & Performance Requirements” table by referring to the “Total Database Disk Space Required / Replica” value.

5.       What is the average transaction log generation rate per storage group each day?  Enter the total logs generated on the server.  This can be obtained from the Exchange 2007 Mailbox Storage Requirements Calculator’s Storage Requirements tab “Server Configuration” table by referring to the “Average Transaction Logs Generated / SG / Day” value.

DPM VSS Backup Configuration

1.       What is the backup rate?  Enter in the rate at which you can backup your Exchange data.  The actual back rate that can be achieved will depend on three things:

a.       Read rate from source LUN – if designed properly, this should not be a huge problem unless you run backup during peak times or you’re running multiple threads from the same set of disks.

b.       Effective write rate at the medium- This is the speed with which DPM can write to the storage pool disks. When doing initialization, the writes are typically sequential in nature. However for express fulls, the writes are typically random in nature.

c.        The network rate – It is recommended that you use a Gbps network connectivity between the Exchange server and the DPM server. DPM can also be configured to use a dedicated NIC to perform the backups thereby getting a higher throughput without loading your corporate network.

2.       What is the restore rate?  Enter the rate at which you can restore your data.

3.       What is the VSS Backup Frequency?  Enter the frequency at which you perform an incremental backup synchronization.  This value determines your point in time copy, and thus affects your recovery point objective.   You can choose from 15 minutes all the way up to once per day.

4.       What is the retention range?  The retention range specifies how long you want to keep a backup so that you can recover it.  After the retention period, the backup is deleted from DPM.

5.       What is the Express Full frequency?  Specify how often you wish to perform an express full backup, either daily or weekly.  Express full backups take more time than an incremental synchronization, but the benefit of more frequent express fulls is that the time for a recovery is reduced since fewer logs need to be played back in order to restore to a point in time.

DPM ExBackup Requirements

This section outlines the capacity requirements for the DPM server.


The Calculations Pane performs all the calculations based on the input factors and outputs the key calculations into the Results Pane. For this blog, I will not delve into the specifics of the calculations, but feel free to review them within the calculator.


Based on the above input factors, the calculator will recommend the following settings.












Backup Configuration

The Backup Configuration table will provide you with

·         The Number of Databases / LUN, which is derived from the LUN Design Architecture model chosen.

·         The Backup Methodology, which in this case, since we are using DPM, will always be a VSS backup.

·         The Backup Frequency, which was an option selected on the input worksheet.

Backup Window Requirements

The Backup Window Requirements table will provide you with

·         The Express Full Backup Window / SG is the amount of time it will take to back up a single storage group via an Express Full backup.  A DPM express full backup is basically a full backup that only needs to transfer the changed blocks since the last express full. Hence this is faster and requires sending lesser data across the network in order to perform the full backup.  You should validate this metric against your Service Level Agreements to determine if it is acceptable.

·         The Incremental or Differential backup Window / SG is the amount of time it will take to perform an incremental synchronization for a single storage group and is based on the number of transaction logs that are generated during the backup window.

DPM Server Configuration

The DPM Server Configuration table will provide you with

·         The Recommended Number of DPM servers needed to support the Exchange infrastructure.  This value is based on the number of storage groups (max 250 per server) or the DPM storage requirements (max 40TB).

·         The Recommended Number of Processors Cores / DPM Server needed to support DPM.  At the time of this writing, Microsoft recommends having 4 processor cores per DPM server.

·         The Recommended RAM Configuration / DPM Server needed to support the DPM activities.  At the time of this writing, Microsoft recommends having 8GB of physical memory.

·         The Recommended Virtual Memory Configuration / DPM Server need to support DPM activities.  This value is based on the amount of data being backed up.

·         The Total Storage Capacity Needed outlines the necessary capacity requirements to back up all the Exchange mailbox servers.

DPM Space Requirements / Exchange Server

The DPM Space Requirements table outlines the replica size and recovery point volume size for each storage group on an Exchange mailbox server.

DPM Protected Group Configuration Data / Exchange Server

The DPM Protected Group Configuration Data table outlines each protected group (based on the LUN Design Architecture and the number of databases housed on each LUN), the synchronization frequency for each protected group, the retention range, and the express full backup schedule.


Hopefully you will find this calculator invaluable in helping to determine your storage requirements for backing up Exchange 2007 using Data Protection Manager 2007. If you have any questions or suggestions, please email dpmcalc AT microsoft DOT com.

 Download the calculator from the attachment to this post.

[The calculator has been updated on 12 June 2009]

Note: This calculator is saved in the new Excel 2007 format. If you are not running Office 2007, then you will need the compatibility pack for Office XP and 2003 which can be obtained from here.

Data Protection Manager 2007 Storage Calculator.xlsx