Disk Management Concepts:Allocating disk space

Applies To: Windows SBS 2008

Before you install Windows SBS 2008, determine the size of the hard disk drive or partition on which to install Windows SBS 2008. There is no set formula for determining a hard disk drive or partition size. The basic principle is to allow enough space for the operating system, applications, and other files that you plan to install. The files for setting up the operating system require approximately 60 GB. It is recommended that you allow considerably more disk space than the minimum. This allows space for a variety of items, including additional components, future service packs, and the paging file that the operating system uses. You also need additional space for the server applications that you plan to install.

Sample disk configurations

The estimates included in the following table are based on typical usage and functionality, but they do not address issues that affect optimal performance. You can use any type of supported hard disk drive for these configurations.


Server Level Hard Disk Drive Configuration


  • Two physical hard disk drives

  • Configured as a RAID 1 mirrored set that contains the following:

    • C volume: 100 GB

    • E volume: 100 GB

    • F volume: 100 GB


  • Three physical hard disk drives

  • Configured as a RAID 5 set that contains the following:

    • C volume: 100 GB

    • E volume: 100 GB

    • F volume: 100 GB


  • Five or more total physical hard disk drives

  • Two disks in a RAID 1 mirrored set that contains the C volume: 100 GB

  • All remaining disks in a RAID 5 set that contains the following:

    • E volume: Half of the available space

    • F volume: Half of the available space

These recommendations take into account the size of the installed operating system, the average size of the data storage that Windows SBS 2008 uses, and the expected data storage growth over the life of the server. The volumes can be partitions on a hard disk drive set, or they can be placed on individual hard disk drives. Because the server can store important data for your users, it is recommended that you use multiple drives and help protect your users’ data by using RAID.

The recommended volume configurations are as follows:

  • C volume   The system drive contains the operating system files, and it leaves room for files and applications such as the pagefile, the installed applications, and the dump files. Do not enable the Volume Shadow Copy Service on this volume. Initially, an installation of Windows SBS 2008 is approximately 20 GB. However, it will likely grow over time as log files, temporary files, and other data accumulates. There is enough available space on the volume for you to install additional applications, which accumulate additional data.

  • D volume   This is the DVD drive, which is used to install Windows SBS 2008 and applications.

  • E volume   This volume contains the data stores, such as the Exchange Server database, Windows Server Update Services, and Windows SharePoint Services databases. Do not enable the Volume Shadow Copy Service for this volume, because it might cause performance issues with Exchange Server.

    • Assuming that 10 people use Exchange Server, and they each need an average of 2 GB, you need to provide 20 GB to store e-mail. Some environments need more room because of larger file sizes or because of retention requirements, so the estimates are based on 40 GB for Exchange Server data. If you provide e-mail services for more than 10 users, this volume should be larger.

    • A typical Windows Server Update Service database is 40 GB. The estimates provide for a 50 GB database.

    • The estimates allow for 10 GB of storage for Windows SharePoint Services.

  • F volume   This volume contains the users’ data, including redirected user folders and shared folders. You should enable the Volume Shadow Copy Service on this volume to help back up the users’ data.

    • Windows SBS 2008 automatically redirects users’ folders. This can include music, pictures, and other types of data that may require a large amount of storage space. The estimates are based on 5 GB of storage per user, with 10 users.

    • You may also store shared data in shared folders on the server. The estimate allows for 50 GB of shared storage.

    • The amount of space that the users’ data requires is the most difficult to estimate. Wherever possible, allow more space for the users’ data.

  • G volume   This volume is optional, and it is not included in the estimates. It contains low priority data that is easily recovered from another source such as a CD or DVD, and that can be excluded from normal backups.

Optional disks

In addition to the internal hard disk drives that are installed on the server, you should consider using external storage drives for backups. Ideally, there are at least two external drives with enough capacity to back up all of the data on the server. When you use external storage drives, they can be taken offsite each night to further protect the data after Backup finishes. It is recommended that the daily backup include all of the data on the server; although over time, this may require more capacity than the backup drives can provide.

Backup can exclude data from the backups based on the volume, but not based on individual folders. If the backups become too large, you can install another external or internal hard disk drive, configure it as the G volume, and then use it to save the excluded data. This is data that does not need to be backed up daily because it is less important or because another backup of the data is available.

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