Primary Partitions

You create primary partitions on basic disks to store data. GPT disks support up to 128 partitions, which can be a mix of required and optional partitions. Every primary partition you create appears in the GPT partition array. If you convert a basic disk that contains primary partitions to a dynamic disk, the primary partitions become simple volumes, and information about them is then stored in the dynamic disk database and not in the GUID partition array.

To create a primary partition, complete the following steps:

1. In Disk Management Graphical View, right-click an area marked Unallocated on a basic disk, and then choose New Simple Volume. This starts the New Simple Volume Wizard. Click Next.
2. The partition is created as a primary partition automatically. Use the Assign Drive Letter Or Path page to assign a drive letter or path. You can also choose Do Not Assign A Drive Letter Or Drive Path if you want to create the partition without assigning a drive letter or path. Click Next.
3. Use the Format Partition page to set the formatting options. If you opt not to format the partition at this time.
4. 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.

LDM Metadata and LDM Data Partitions

Windows Server 2008 creates LDM Metadata and LDM Data partitions when you convert a basic GPT disk to a dynamic GPT disk. The LDM Metadata partition is 1 MB in size and is used to store the partitioning information needed for the conversion. The LDM Data partition is the partition in which the actual dynamic volumes are created.

The LDM Data partition is used to represent sections of unallocated space on the converted disk as well as sections that had basic partitions that are now dynamic volumes. For example, if a disk had a primary boot partition that spanned the whole disk, the converted disk will have a single LDM Data partition. If a disk had a boot partition and other primary partitions, it will have two LDM Data partitions after the conversion: one for the boot volume, and one for all the rest of the partitions. Although the LDM Metadata and LDM Data partitions are not shown in Disk Management and do not receive drive letters or mount points, you are able to use this space by creating primary partitions as discussed in the previous section.

OEM or Unknown Partitions

GPT disks can have partitions that are specific to OEM implementations, and your vendor documentation should describe what they are used for. The Windows operating system displays these partitions in Disk Management as Healthy (Unknown Partition). You cannot, however, manipulate these partitions in Disk Management or DiskPart. Additionally, if an unknown partition lies between two known partitions on a GPT disk, you won't be able to convert the disk from the basic disk type to the dynamic disk type.