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What Is NTFS?

Updated: March 28, 2003

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

What Is NTFS?

In this section

A file system is a part of the operating system that determines how files are named, stored, and organized on a volume. A file system manages files and folders, and the information needed to locate and access these items by local and remote users. Microsoft Windows Server 2003 supports both the FAT and NTFS file systems.

NTFS allows you to gain the maximum benefits for the needs of today’s enterprise business environments from Windows Server 2003, such as increased security, more robust and reliable performance, as well as a design for greater storage growth, features not found in FAT.

Common NTFS Scenarios

This section describes a few scenarios in which NTFS should be used as the file system on a server running Windows Server 2003.

Increasing reliability

NTFS uses its log file and checkpoint information to restore the consistency of the file system when the computer is restarted in the event of a system failure. In the event of a bad-sector error, NTFS dynamically remaps the cluster containing the bad sector and allocates a new cluster for the data, as well as marking the cluster as bad and no longer using it. For example, by formatting a POP3 mail server with NTFS, the mail store can offer logging and recovery. In the event of a server crash, NTFS can recover data by replaying its log files.

Increasing security

NTFS allows you to set permissions on a file or folder, and specify the groups and users whose access you want to restrict or allow, and then select the type of access. NTFS also supports the Encrypting File System (EFS) technology used to store encrypted files on NTFS volumes. Any intruder who tries to access your encrypted files is prevented from doing so, even if that intruder has physical access to the computer. For example, a POP3 mail server, when formatted with an NTFS file system, provides increased security for the mail store, security that would not be available should the server be formatted with the FAT file system.

Supporting large volumes

NTFS allows you to create an NTFS volume up to 16 terabytes using the default cluster size (4 KB) for large volumes. You can create NTFS volumes up to 256 terabytes using the maximum cluster size of 64 KB. NTFS also supports larger files and more files per volume than FAT. In addition, NTFS manages disk space more efficiently than FAT by using smaller cluster sizes. For example, a 30-GB NTFS volume uses 4-KB clusters. The same volume formatted by using FAT32 uses 16-KB clusters. Using smaller clusters reduces wasted space on hard disks. NTFS supports the many capabilities of dynamic disks for managing large storage requirements.

Limited space on a volume

If your organization has limited space on a volume, NTFS provides support for increasing storage on a server with limited disk space.

  • Disk quotas allow you to track and control user disk space usage for NTFS volumes.

  • NTFS supports compression as well as adding unallocated space from the same disk or from another disk to increase the size of an NTFS volume.

  • Mounted volumes allow you to mount a volume at any empty folder on a local NTFS volume if you run out of drive letters or need to create additional space that is accessible from an existing folder.

Using features available only in NTFS

NTFS has a number of features that are not available if you are using a FAT file system. These include:

  • Distributed link tracking. Maintains the integrity of shortcuts and OLE links. You can rename source files, move them to NTFS volumes on different computers within a Windows Server 2003 or Windows 2000 domain, or change the computer name or folder name that stores the target without breaking the shortcut or OLE links.

  • Sparse files. Large, consecutive areas of zeros. NTFS manages sparse files by tracking the starting and ending point of the sparse file, as well as its useful (non-zero) data. The unused space in a sparse file is made available as free space.

  • NTFS change journal. Provides a persistent log of changes made to files on a volume. NTFS maintains the change journal by tracking information about added, deleted, and modified files for each volume.

  • Hard links. NTFS-based links to a file on an NTFS volume. By creating hard links, you can have a single file in multiple folders without duplicating the file. You can also create multiple hard links for a file in a folder if you use different file names for the hard links. Because all of the hard links reference the same file, applications can open any of the hard links and modify the file.

Using Windows Server 2003 features that require NTFS

Windows Server 2003 includes a number of features that require NTFS as the file system. A few of these features include:

  • Volume Shadow Copy service. Service that provides an infrastructure for creating highly accurate, point-in-time shadow copies. These copies of a single volume or multiple volumes can be made without affecting the performance of a production server. The Volume Shadow Copy Service can produce accurate shadow copies by coordinating with business applications, backup applications, and storage hardware.

  • Distributed File System (DFS). Strategic storage management solution in Windows Server 2003 that enables you to group shared folders located on different servers logically by transparently connecting them to one or more hierarchical namespaces.

  • File System Replication (FRS) Technology that replicates files and folders stored in the SYSVOL shared folder on domain controllers and Distributed File System (DFS) shared folders. When FRS detects that a change has been made to a file or folder within a replicated shared folder, FRS replicates the updated file or folder to other servers.

In addition, NTFS is required before you can promote a server running Windows Server 2003 to a domain controller that hosts the Active Directory directory service.

If the volume is not formatted with the NTFS file system, these Windows Server 2003 features will not be available.


  • Although NTFS is the preferred file system for hard disks, NTFS cannot be used on removable media. Instead, Windows Server 2003 uses FAT12 for formatting floppy disks, and FAT32 for formatting flash media and DVD-RAM discs.

Operating System and NTFS Compatibility

NTFS is not supported on versions of Microsoft Windows earlier than Windows NT 4.0 and Windows 2000 Professional or MS-DOS. The table Operating System and NTFS Compatibility shows which operating systems support NTFS.

Operating System and NTFS Compatibility


Operating System NTFS

Windows XP

Table Bullet

Windows Server 2003

Table Bullet

Windows 2000

Table Bullet

Windows NT 4.0

Table Bullet

Windows 95 OSR2, Windows 98, and Windows Millennium Edition


Windows 95 (prior to OSR2)





  • Computers running Windows NT 4.0 require Service Pack 4 or later to access NTFS volumes previously mounted by Windows 2000, Windows XP, or Windows Server 2003.

Dependencies on Other Technologies

NTFS depends on the following technologies:

Basic Disks and Volumes

Basic disks and basic volumes are the storage types most often used with Windows operating systems. The term basic disk refers to a disk that contains basic volumes, such as primary partitions and logical drives. The term basic volume refers to a partition on a basic disk. Basic disks, which are found in both x86-based and Itanium-based computers, provide a simple storage solution that can accommodate changing storage requirements.

Dynamic Disks and Volumes

Dynamic disks can use the master boot record (MBR) or GUID partition table (GPT) partitioning scheme. All volumes on dynamic disks are known as dynamic volumes. Dynamic disks were first introduced with Windows 2000 and provide features that basic disks do not.

Related Technology

NTFS is related to the following technology:

FAT file system

The File Allocation Table (FAT) file system is an older file system that relies on an allocation table to keep track of files and folders on a volume. Windows Server 2003 supports both FAT16 and FAT32 file systems.

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