Difference between revisions of "GUID Partition Table"

From ArchWiki
Jump to: navigation, search
(Advantages of GPT: moved to Partitioning#Advantages of GPT)
(About the GUID Partition Table: link to Partitioning#GUID Partition Table)
Line 33: Line 33:
 
  | Last logical sector of the disk or Last 512 bytes || Secondary GPT Header - Contains the Unique Disk GUID, Location of the Secondary Partition Table, Number of possible entries in the partition table, CRC32 checksums of itself and the Secondary Partition Table, Location of the Primary GPT Header. This header can be used to recover GPT info in case the primary header is corrupted.
 
  | Last logical sector of the disk or Last 512 bytes || Secondary GPT Header - Contains the Unique Disk GUID, Location of the Secondary Partition Table, Number of possible entries in the partition table, CRC32 checksums of itself and the Secondary Partition Table, Location of the Primary GPT Header. This header can be used to recover GPT info in case the primary header is corrupted.
 
|}
 
|}
 +
 +
See [[Partitioning#GUID Partition Table]].
  
 
=== Kernel Support ===
 
=== Kernel Support ===

Revision as of 12:51, 4 September 2016

zh-CN:GUID Partition Table

Merge-arrows-2.pngThis article or section is a candidate for merging with Partitioning.Merge-arrows-2.png

GUID Partition Table (GPT) is a partitioning scheme that is part of the Unified Extensible Firmware Interface specification; it uses a globally unique identifier for qualifying devices. It is the next generation partitioning scheme designed to succeed the Master Boot Record partitioning scheme method. It evolved to deal with several shortcomings of the MBR partitioning scheme method and offers additional advantages.

About the GUID Partition Table

GUID Partition Table (GPT) uses GUIDs (or UUIDs in linux world) to define partitions and its types, hence the name. The GPT consists of:

Location in the HDD Purpose
First logical sector of the disk or First 512 bytes Protective MBR - Same as a normal MBR but the 64-byte area contains a single 0xEE type Primary partition entry defined over the entire size of the disk or in case of >2 TiB, upto a partition size of 2 TiB.
Second logical sector of the disk or Next 512 bytes Primary GPT Header - Contains the Unique Disk GUID, Location of the Primary Partition Table, Number of possible entries in partition table, CRC32 checksums of itself and the Primary Partition Table, Location of the Secondary (or Backup) GPT Header
16 KiB (by default) following the second logical sector of the disk Primary GPT Table - 128 Partition entries (by default, can be higher), each with an entry of size 128 bytes (hence total of 16 KiB for 128 partition entries). Sector numbers are stored as 64-bit LBA and each partition has a Partition Type GUID and a Unique Partition GUID.
16 KiB (by default) before the last logical sector of the disk Secondary GPT table - It is byte-for-byte identical to the Primary table. Used mainly for recovery in case the primary partition table is damaged.
Last logical sector of the disk or Last 512 bytes Secondary GPT Header - Contains the Unique Disk GUID, Location of the Secondary Partition Table, Number of possible entries in the partition table, CRC32 checksums of itself and the Secondary Partition Table, Location of the Primary GPT Header. This header can be used to recover GPT info in case the primary header is corrupted.

See Partitioning#GUID Partition Table.

Kernel Support

CONFIG_EFI_PARTITION option in the kernel config enables GPT support in the kernel (despite the name EFI PARTITION). This options must be built-in the kernel and not compiled as a loadable module. This option is required even if GPT disks are used only for data storage and not for booting. This option is enabled by default in Arch's linux and linux-lts kernels in [core] repo. In case of a custom kernel enable this option by doing CONFIG_EFI_PARTITION=y.

See also