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Understanding File System Options Page 3

By Jason Zandri (Send Email)
Posted Jul 24, 2003


NTFS File Systems

NTFS, which stands for New Technology File System, is the preferred file system for all computers running Windows Server 2003. If you are running Windows NT 4.0 Service Pack 4 or later, you can read basic volumes formatted by using NTFS 5 locally on dual boot systems. Windows Server 2003, Windows 2000, and Windows XP Professional can all read NTFS partitions on both basic and dynamic volumes.

(Computers systems accessing either version of NTFS across networks are not affected. Version differences are usually considered only in local and dual boot situations.)

The following NTFS features are available under version 5:
  • File and folder permissions
  • Encryption
  • Disk quotas
  • File compression
  • Mounted drives
  • Hard links
  • Distributed link tracking
  • Sparse files
  • Multiple data streams
  • POSIX compliance
  • NTFS change journal
  • Indexing service

Detailed information on these features can be found in both the Microsoft Windows XP Professional Resource Kit Documentation and online.

If you are running Windows Server 2003 in a dual boot scenario with a system running Windows NT 4.0 Service Pack 4 or later, most of the NTFS 5 features are not available. Most read and write operations are permitted, as they do not attempt to make use of most NTFS 5 features.

Issues that may occur under this type of configuration include:

  • Windows NT4 cannot perform any operations that make use of reparse points.
  • When running Windows NT4 on a multiple-boot configuration that also runs Windows XP Professional, Windows NT4 ignores disk quotas implemented by Windows XP Professional.
  • Windows NT4 cannot perform any operations on files encrypted by Windows XP Professional.
  • Windows NT4 cannot perform any operations on sparse files.
  • Windows NT4 ignores the change journal setup under Windows XP Professional.

The NTFS file system supports drives up to 16 EB, in theory. However, because partition tables on basic disks (disks that include a master boot record) support partition sizes up to only 2 TB, dynamic volumes are a requirement when creating NTFS partitions more than 2 TB in size. Maximum volume and partition sizes start at 2 TB and range upward to almost 16 TB -- dependent on whether basic or dynamic volumes are used and whether the volume is formatted with a standard allocation unit size of 4 KB.

Windows 2000, Windows XP Professional, and Windows Server 2003 manage dynamic volumes in a special database instead of in the partition table. Therefore dynamic volumes are not subject to the 2-TB physical limit imposed by the partition table. This is why dynamic NTFS volumes can be as large as the maximum volume size supported by NTFS.

Default NTFS File System Cluster Sizes
Partition Size
NTFS
7 MB to 16 MB 512 bytes
17 MB to 32 MB 512 bytes
33 MB to 64 MB 512 bytes
65 MB to 128 MB 512 bytes
129 MB to 256 MB 512 bytes
257 MB to 512 MB 512 bytes
513 MB to 1,024 MB 1,024 bytes
1,025 MB to 2 GB 2,048 bytes
2 GB to 4 GB 4,096 bytes
4 GB to 8 GB 4,096 bytes
8 GB to 16 GB 4,096 bytes
16 GB to 32 GB 4,096 bytes
32 GB to 2 TB 4,096 bytes

Advantages of NTFS are as follows:

  • NTFS uses standard transaction logging and recovery techniques. By using the log file and checkpoint information to automatically restore the consistency of the file system in the event of a failure, NTFS, for the most part, maintains the consistency of the data on the volume and the volume itself.
  • NTFS supports compression on volumes, folders, and files. Files compressed on an NTFS volume can be read and written by any Windows-based application without first being decompressed by another program. Decompression happens automatically (think of a ZIP utility on-the-fly) during the file read. The file is compressed again when it is closed or saved.
  • NTFS does not restrict the number of entries to 512 in the root folder.
  • Windows 2000 and Windows XP can format partitions up to 2 TBs.
  • NTFS manages disk space efficiently by using smaller clusters (see the Default Cluster Sizes table following the list of disadvantages).
  • The boot sector is backed up to a sector at the end of the volume.
  • You can set permissions on shares, folders, and files that specify which groups and users have access, and what level of access is permitted on NTFS partitions.
  • NTFS supports a native encryption system (EFS), to prevent unauthorized access to file contents.
  • Reparse points enable new features such as volume mount points.
  • Disk quotas can be set to limit the amount of usage allowed by end users.
  • A change journal tracks changes made to files.
  • NTFS supports distributed link tracking to maintain the integrity of shortcuts and OLE links.
  • NTFS supports sparse files so that very large files can be written to disk while requiring only a small amount of storage space.

Not surprisingly, NTFS also has disadvantages:

  • NTFS volumes are not locally accessible from MS-DOS, Windows 95, Windows 98, and Windows Millennium Edition operating systems.
  • Many advanced features of NTFS included with version 5 are not available in Windows NT.
  • On small partitions with mostly small files, the overhead of managing the NTFS file system can cause a slight performance drop in comparison to FAT.
  • Floppy disks cannot be formatted as NTFS
More detailed answers to questions about the NTFS File System, is available in the Microsoft Windows XP Professional Resource Kit Documentation.

Default Cluster Sizes for Partitions Under Windows Server 2000

Partition Size Cluster Size
  FAT16 FAT32 NTFS
7 MB-16 MB 2 KB (FAT12) Not supported 512 bytes
17 MB-32 MB 512 bytes Not supported 512 bytes
33 MB-64 MB 1 KB 512 bytes 512 bytes
65 MB-128 MB 2 KB 1 KB 512 bytes
129 MB-256 MB 4 KB 2 KB 512 bytes
257 MB-512 MB 8 KB 4 KB 512 bytes
513 MB-1,024 MB 16 KB 4 KB 1 KB
1,025 MB-2 GB 32 KB 4 KB 2 KB
2 GB-4 GB 64 KB 4 KB 4 KB
4 GB-8 GB Not supported 4 KB 4 KB
8 GB-16 GB Not supported 8 KB 4 KB
16 GB-32 GB Not supported 16 KB 4 KB
32 GB-2 TB Not supported Not supported 4 KB

Summary and Various Quick Points

  • FAT volumes smaller than 16 MB are formatted as FAT12.
  • FAT12 is used only on floppy disks and volumes smaller than 16 MB
  • FAT16 volumes larger than 2 GB are not locally accessible from computers running MS-DOS, Windows 95, Windows 98, Windows Millennium Edition and many other operating systems.
  • FAT32 volumes can theoretically be as large as 2 TB; Windows Server 2003, Windows 2000 and Windows XP limit the maximum size FAT32 volume that it can format to 32 GB. (Windows Server 2003, Windows 2000 and Windows XP Professional can read and write to larger FAT32 volumes formatted by other operating systems.)
  • NTFS volumes can theoretically be as large as 16 EB, but the practical limit is 2 TB.
  • The user can specify the cluster size when an NTFS volume is formatted. However, NTFS compression is not supported for cluster sizes larger than 4 KB.
  • Not supported means "Not supported by Microsoft." In some "chance" cases, you may be able to perform a function that is not normally supported.

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