2 TB: Using GUID File Allocation Tables (GPT GUID Partition Table)

2 TB Drives have been around a while and certainly building raid arrays over 2 TB has been possible for quite some time. If you haven’t stumbled across this read on.

Why GPT?

  • GUID Partition Table disks can grow to a very large size. As of July 2001, the Microsoft implementation supports a hard disk of up to 18 EB (Exabyte equal 1000 Terabytes). It is not that I am predicting Exabyte drives soon but more that Master Boot Record tops out at 2 TB. GPT is the partition table to use if you plan on exceeding 2 TB.
  • How big can a GPT disk be?
    In theory, a GPT disk can be up to 2^64 logical blocks in length. Logical blocks are commonly 512 bytes in size. The maximum partition (and disk) size is a function of the operating system version. Windows XP and the original release of Windows Server 2003 have a limit of 2TB per physical disk, including all partitions. For Windows Server 2003 SP1 Windows XP x64 edition, and later versions, the maximum raw partition of 18 exabytes can be supported. (Windows file systems currently are limited to 256 terabytes each.)

More Information:

Microsoft has a Knowledge Base Article FAQ around GPT:

Microsoft has another article covering:
How to set up dynamic boot partition mirroring on GUID partition table (GPT) disks in Windows Server 2008

Jeff Loucks
Available Technology
Available Technology
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