Managing MBR Disk Partitions on Basic Disks

A disk using the MBR partition style can have up to four primary partitions and up to one extended partition. This allows you to configure MBR disks in one of two ways: using one to four primary partitions or using one to three primary partitions and one extended partition. After you partition a disk, you format the partitions to assign drive letters or mount points.

The drive letters that are available depend on how a system is configured. The initial drive letters used by a computer are assigned during installation of the operating system. Setup does this by scanning all fixed hard disks as they are enumerated.

For MBR disks, Setup assigns a drive letter to the first primary partition starting with C. Setup then scans fl oppy/Zip disks and assigns drive letters starting with A. Afterward, Setup scans CD/DVD-ROM drives and assigns the next available letter starting with D. Finally, Setup scans all fixed hard disks and assigns drive letters to all remaining primary partitions.

With GPT disks, Setup assigns drive letters to all primary partitions on the GPT disk starting with C. Setup then scans fl oppy/Zip drives and assigns the next available drive letter starting with A. Finally, Setup scans CD/DVD-ROM drives and assigns the next available letter starting with D.

Creating Partitions and Simple Volumes

Windows Server 2008 simplifi es the Disk Management user interface by using one set of dialog boxes and wizards for both partitions and volumes. The first three volumes on a basic drive are created automatically as primary partitions. If you try to create a fourth volume on a basic drive, the remaining free space on the drive is converted automatically to an extended partition with a logical drive of the size you designate by using the new volume feature it created in the extended partition. Any subsequent volumes are created in the extended partitions and logical drives automatically.

In Disk Management, you create partitions, logical drives, and simple volumes by following these steps:

1. In Disk Management's Graphical View, right-click an unallocated or free area on the disk and then choose New Simple Volume. This starts the New Simple Volume Wizard. Read the Welcome page and then click Next.
2. Click Next to display the Specify Volume Size page. Then use the Simple Volume Size In MB field to specify how much of the available disk space you want to use for the volume. Keep the following in mind before you set the size and click Next:
   • You can size a primary partition to fill an entire disk, or you can size it as appropriate for the system you're configuring. Because of the availability of FAT32 and NTFS, you no longer must worry about the 4-GB volume size and 2-GB file size limits that applied to 16-bit FAT systems. This allows you to size partitions as you see fit.
   • You can size extended partitions to fill any available unallocated space on a disk. Because an extended partition can contain multiple logical drives, each with their own file system, consider carefully how you might want to size logical drives before creating the extended partition. Additionally, if a drive already has an extended partition or is removable, you won't be able to create an extended partition.
3. If you are creating a primary partition, use the Assign Drive Letter Or Path page, to assign a drive letter or path. You can do one of the following:
   • Assign a drive letter by choosing Assign The Following Drive Letter and then selecting an available drive letter in the selection list provided. Generally, the drive letters E through Z are available for use (drive letters A and B are used with fl oppy/Zip drives, drive C is for the primary partition, and drive D is for the computer's CD/DVD-ROM drive).
   • Mount a path by choosing Mount In The Following Empty NTFS Folder and then typing the path to an existing folder. You can also click Browse to search for or create a folder.
   • Use Do Not Assign A Drive Letter Or Drive Path To if you want to create the partition without assigning a drive letter or path.
4. Using the Format Partition page, you can opt to not format the partition at this time or to select the formatting options to use. Formatting creates a file system in the new partition and permanently deletes any existing data. The formatting options are as follows:
   • File System sets the file system type as FAT, FAT32, or NTFS. FAT volumes can be up to 4 GB in size and have a maximum file size limit of 2 GB. FAT32 volumes can be up to 32 GB in size (a limitation of Windows Server 2008) and have a maximum file size of 4 GB. NTFS files and volumes can be up to 2 TB in size on MBR disks and up to 18 EB on GPT disks.
     Choose the Partition Format with Care
     If you don't know which file system to use, it is best in most cases to use NTFS. Only NTFS volumes can also use advanced file access permissions, compression, encryption, disk quotas, shadow copies, remote storage, and sparse files. There are exceptions, of course. If you want to be able to boot multiple operating systems, you might want to use FAT or FAT32. When a boot partition is formatted using FAT, you are able to boot to just about any operating system. When a boot partition is FAT32, you are able to boot to any version of the Windows operating system except Windows NT 4.0 and Windows 95 OSR1. Further, because FAT32 doesn't have the journaling overhead of NTFS, it is more effi cient at handling large files that change frequently, and particularly files that have small incremental changes, such as log files. This means in some cases that FAT32 will read and write files faster than NTFS. However, if you use FAT32, you won't be able to use any of the advanced file system features of Windows Server 2008.
   • Allocation Unit Size sets the cluster size for the file system. This is the basic unit in which disk space is allocated, and by default, it is based on the size of the volume.
     Choosing an Allocation Unit Size
     In most cases the default size is what is best but you can override this feature by setting a different value. If you use lots of small files, you might want to use a smaller cluster size, such as 512 or 1024 bytes. With these settings, small files use less disk space. Although sizes of up to 256 KB are allowed, you will not be able to use compression on NTFS if you use a size larger than 4 KB.
   • Volume Label sets a text label for the partition that is used as its volume name. If you must change a partition's volume label, you can do this from the command line by using the Label command or from Windows Explorer by right-clicking the volume, selecting Properties, and then typing a new label on the General tab.
   • Perform A Quick Format specifies that you want to format the partition without checking for errors. Although you can use this option to save you a few minutes, it's better to check for errors because this allows Disk Management to mark bad sectors on the disk and lock them out.
   • Enable File And Folder Compression turns on compression so that files and folders on this partition are compressed automatically. Compression is available only for NTFS.
5. Click Next. The final page shows you the options you've selected. If the options are correct, click Finish. The wizard then creates the partition and configures it.