Section: Maintenance Commands (8)
Updated: July 2013
ntfsresize [OPTIONS] --info(-mb-only) DEVICE
The ntfsresize program safely resizes Windows XP, Windows Server 2003, Windows 2000, Windows NT4 and Longhorn NTFS filesystems without data loss. All NTFS versions are supported, used by 32-bit and 64-bit Windows. Defragmentation is NOT required prior to resizing because the program can relocate any data if needed, without risking data integrity.
Ntfsresize can be used to shrink or enlarge any NTFS filesystem located on an unmounted DEVICE (usually a disk partition). The new filesystem will fit in a DEVICE whose desired size is SIZE bytes. The SIZE parameter may have one of the optional modifiers k, M, G, which means the SIZE parameter is given in kilo-, mega- or gigabytes respectively. Ntfsresize conforms to the SI, ATA, IEEE standards and the disk manufacturers by using k=10^3, M=10^6 and G=10^9.
If both --info(-mb-only) and --size are omitted then the NTFS filesystem will be enlarged to match the underlying DEVICE size.
To resize a filesystem on a partition, you must resize BOTH the filesystem and the partition by editing the partition table on the disk. Similarly to other command line filesystem resizers, ntfsresize doesn't manipulate the size of the partitions, hence to do that you must use a disk partitioning tool as well, for example fdisk?(8). Alternatively you could use one of the many user friendly partitioners that uses ntfsresize internally, like Mandriva's DiskDrake, QTParted, SUSE/Novell's YaST Partitioner, IBM's EVMS, GParted or Debian/Ubuntu's Partman.
IMPORTANT! It's a good practice making REGULAR BACKUPS of your valuable data, especially before using ANY partitioning tools. To do so for NTFS, you could use ntfsclone?(8). Don't forget to save the partition table as well!
If you wish to shrink an NTFS partition, first use ntfsresize to shrink the size of the filesystem. Then you could use fdisk?(8) to shrink the size of the partition by deleting the partition and recreating it with the smaller size. Do not make the partition smaller than the new size of NTFS otherwise you won't be able to boot. If you did so notwithstanding then just recreate the partition to be as large as NTFS.
To enlarge an NTFS filesystem, first you must enlarge the size of the underlying partition. This can be done using fdisk?(8) by deleting the partition and recreating it with a larger size. Make sure it will not overlap with an other existing partition. You may enlarge upwards (first sector unchanged) or downwards (last sector unchanged), but you may not enlarge at both ends in a single step. If you merge two NTFS partitions, only one of them can be expanded to the merged partition. After you have enlarged the partition, you may use ntfsresize to enlarge the size of the filesystem.
When recreating the partition by a disk partitioning tool, make sure you create it at the same starting sector and with the same partition type as before. Otherwise you won't be able to access your filesystem. Use the 'u' fdisk command to switch to the reliable sector unit from the default cylinder one.
Below is a summary of all the options that ntfsresize accepts. Nearly all options have two equivalent names. The short name is preceded by and the long name is preceded by -. Any single letter options, that don't take an argument, can be combined into a single command, e.g. -fv is equivalent to -f -v. Long named options can be abbreviated to any unique prefix of their name.
Practically the smallest shrunken size generally is at around "used space" + (20-200 MB). Please also take into account that Windows might need about 50-100 MB free space left to boot safely.
If used in association with option --expand, ntfsresize will determine the smallest downwards expansion size and the possible increments to the size. These are exact byte counts which must not be rounded. This option may be used after the partition has been expanded provided the upper bound has not been changed.
This option never causes any changes to the filesystem, the partition is opened read-only.
If the expansion is interrupted for some reason (power outage, etc), you may restart the resizing, as the original data and metadata have been kept unchanged.
Note : expanding a Windows system partition and filesystem downwards may lead to the registry or some files not matching the new system layout, or to some important files being located too far from the beginning of the partition, thus making Windows not bootable.
Please note, ntfsresize always marks the filesystem for consistency check before a real resize operation and it leaves that way for extra safety. Thus if NTFS was marked by ntfsresize then it's safe to use this option. If you need to resize several times without booting into Windows between each resizing steps then you must use this option.
Prior using this option, it's strongly recommended to make a backup by ntfsclone?(8) using the --rescue option, then running 'chkdsk /f /r volume:' on Windows from the command line. If the disk guarantee is still valid then replace it. It's defected. Please also note, that no software can repair these type of hardware errors. The most what they can do is to work around the permanent defects.
This option doesn't have any effect if the disk is flawless.
No reliability problem is known. If you need help please try the Ntfsresize FAQ first (see below) and if you don't find your answer then send your question, comment or bug report to the development team:
There are a few very rarely met restrictions at present: filesystems having unknown bad sectors, relocation of the first MFT extent and resizing into the middle of a $MFTMirr extent aren't supported yet. These cases are detected and resizing is restricted to a safe size or the closest safe size is displayed.
Ntfsresize schedules an NTFS consistency check and after the first boot into Windows you must see chkdsk running on a blue background. This is intentional and no need to worry about it. Windows may force a quick reboot after the consistency check. Moreover after repartitioning your disk and depending on the hardware configuration, the Windows message System Settings Change may also appear. Just acknowledge it and reboot again.
The disk geometry handling semantic (HDIO_GETGEO ioctl) has changed in an incompatible way in Linux 2.6 kernels and this triggered multitudinous partition table corruptions resulting in unbootable Windows systems, even if NTFS was consistent, if parted?(8) was involved in some way. This problem was often attributed to ntfsresize but in fact it's completely independent of NTFS thus ntfsresize. Moreover ntfsresize never touches the partition table at all. By changing the 'Disk Access Mode' to LBA in the BIOS makes booting work again, most of the time. You can find more information about this issue in the Troubleshooting section of the below referred Ntfsresize FAQ.
Many thanks to Anton Altaparmakov and Richard Russon for libntfs, the excellent documentation and comments, to Gergely Madarasz, Dewey M. Sasser and Miguel Lastra and his colleagues at the University of Granada for their continuous and highly valuable help, furthermore to Erik Meade, Martin Fick, Sandro Hawke, Dave Croal, Lorrin Nelson, Geert Hendrickx, Robert Bjorkman and Richard Burdick for beta testing the relocation support, to Florian Eyben, Fritz Oppliger, Richard Ebling, Sid-Ahmed Touati, Jan Kiszka, Benjamin Redelings, Christopher Haney, Ryan Durk, Ralf Beyer, Scott Hansen, Alan Evans for the valued contributions and to Theodore Ts'o whose resize2fs?(8) man page originally formed the basis of this page.
ntfsresize is part of the ntfs-3g package and is available from:
Ntfsresize related news, example of usage, troubleshooting, statically linked binary and FAQ (frequently asked questions) are maintained at:
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