IBM 88554RU Installation Guide - Page 151

Microsoft Reserved Partition The Microsoft Reserved Partition (MSR partition) reserves space on each disk drive for subsequent use by the operating system software. For example, dynamic disk configuration is stored in the MSR partition. During the installation, the MSR partition is automatically created. When initially created, the size of the MSR partition depends on the size of the disk drive: On drives less than 16 GB in size, the MSR partition is 32 MB. On drives greater than or equal to 16 GB, the MSR partition is 128 MB. Every GPT disk used by Windows must contain an MSR partition. The order of the partitions on the disk should be ESP (if the disk is a boot disk), MSR partition, primary data partition(s). It is particularly important that the MSR partition is created before other primary data partitions. Note: Each Windows boot drive must contain an ESP, an MSR partition, and at least one basic data partition that contains the operating system. Each GPT data drive must contain at least an MSR partition and one basic data partition. The MSR partition is not accessible to the operating system users by any means. The order of partitions on the Windows boot disk is shown in Figure 4-39. Protective MBR GUID Partition Table EFI System Partition (ESP) Microsoft Reserved Partition (MSR) Data partition(s) Figure 4-39 Windows boot GPT disk structure For information on the partitioning required by a Windows 64-bit installation, see: http://www.microsoft.com/technet/prodtechnol/winxppro/reskit/prkb_cnc_helm.asp GPT disks The dynamic disk concept introduced in Windows 2000 is not affected by introducing GUID Partition Table (GPT) disks in Windows Server 2003. Both Master Boot Record (MBR) and GPT disks can be present in a single dynamic disk group. Volume sets can span both MBR and GPT disks. Chapter 4. Installation 137