Linux NTFS - NTFSCLONE (8)

NAME

ntfsclone - Efficiently clone, image, restore or rescue an NTFS

SYNOPSIS

ntfsclone [OPTIONS] SOURCE
ntfsclone --save-image [OPTIONS] SOURCE
ntfsclone --restore-image [OPTIONS] SOURCE
ntfsclone --metadata [OPTIONS] SOURCE

DESCRIPTION

ntfsclone will efficiently clone (copy, save, backup, restore) or rescue an NTFS filesystem to a sparse file, image, device (partition) or standard output. It works at disk sector level and copies only the used data. Unused disk space becomes zero (cloning to sparse file), encoded with control codes (saving in special image format), left unchanged (cloning to a disk/partition) or filled with zeros (cloning to standard output).

ntfsclone can be useful to make backups, an exact snapshot of an NTFS filesystem and restore it later on, or for developers to test NTFS read/write functionality, troubleshoot/investigate users’ issues using the clone without the risk of destroying the original filesystem.

The clone, if not using the special image format, is an exact copy of the original NTFS filesystem from sector to sector thus it can be also mounted just like the original NTFS filesystem. For example if you clone to a file and the kernel has loopback device and NTFS support then the file can be mounted as

mount -t ntfs -o loop ntfsclone.img /mnt/ntfsclone

SPARSE FILES

A file is sparse if it has unallocated blocks (holes). The reported size of such files are always higher than the disk space consumed by them. The du command can tell the real disk space used by a sparse file. The holes are always read as zeros. All major Linux filesystem like, ext2, ext3, reiserfs, Reiser4, JFS and XFS, supports sparse files but for example the ISO 9600 CD-ROM filesystem doesn’t.

HANDLING LARGE SPARSE FILES

As of today Linux provides inadequate support for managing (tar, cp, gzip, gunzip, bzip2, bunzip2, cat, etc) large sparse files. The only main Linux filesystem having support for efficient sparse file handling is XFS by the XFS_IOC_GETBMAPX ioctl. However none of the common utilities supports it. This means when you tar, cp, gzip, bzip2, etc a large sparse file they will always read the entire file, even if you use the "sparse support" options.

bzip2 compresses large sparse files much better than gzip but it does so also much slower. Moreover neither of them handles large sparse files efficiently during uncompression from disk space usage point of view.

At present the most efficient way, both speed and space-wise, to compress and uncompress large sparse files by common tools is using tar with the options -S (handle sparse files "efficiently") and -j (filter the archive through bzip2). Although tar still reads and analyses the entire file, it doesn’t pass on the large data blocks having only zeros to filters and it also avoids writing large amount of zeros to the disk needlessly. But since tar can’t create an archive from the standard input, you can’t do this in-place by just reading ntfsclone standard output.

THE SPECIAL IMAGE FORMAT

It’s also possible, actually it’s recommended, to save an NTFS filesystem to a special image format. Instead of representing unallocated blocks as holes, they are encoded using control codes. Thus, the image saves space without requiring sparse file support. The image format is ideal for streaming filesystem images over the network and similar, and can be used as a replacement for Ghost or Partition Image if it is combined with other tools. The downside is that you can’t mount the image directly, you need to restore it first.

To save an image using the special image format, use the -s or the --save-image option. To restore an image, use the -r or the --restore-image option. Note that you can restore images from standard input by using ’-’ as the SOURCE file.

METADATA-ONLY CLONING

One of the features of ntfsclone is that, it can also save only the NTFS metadata using the option -m or --metadata and the clone still will be mountable. In this case all non-metadata file content will be lost and reading them back will result always zeros.

The metadata-only image can be compressed very well, usually to not more than 1-3 MB thus it’s relatively easy to transfer for investigation, troubleshooting.

In this mode of ntfsclone, NONE of the user’s data is saved, including the resident user’s data embedded into metadata. All is filled with zeros. Moreover all the file timestamps, deleted and unused spaces inside the metadata are filled with zeros. Thus this mode is inappropriate for example for forensic analyses.

Please note, filenames are not wiped out. They might contain sensitive information, so think twice before sending such an image to anybody.

OPTIONS

Below is a summary of all the options that ntfsclone accepts. 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. -fm is equivalent to -f -m.

-o, --output FILE
	Clone NTFS to the non-existent FILE. If FILE is ’-’ then clone to the standard output.
-O, --overwrite FILE
	Clone NTFS to FILE, overwriting if exists.
-s, --save-image
	Save to the special image format. This is the most efficient way space and speed-wise if imaging is done to the standard output, e.g. for image compression, encryption or streaming through a network.
-r, --restore-image
	Restore from the special image format specified by SOURCE. If the SOURCE is ’-’ then the image is read from the standard input.
--rescue
	Ignore disk read errors so disks having bad sectors, e.g. dying disks, can be rescued the most efficiently way, with minimal stress on them. Ntfsclone works at the lowest, sector level in this mode too thus more data can be rescued. The contents of the unreadable sectors are filled by character ’?’ and the beginning of such sectors are marked by "BadSectoR\0".
-m, --metadata
	Clone ONLY METADATA (for NTFS experts). Moreover only cloning to a file is allowed. You can’t metadata-only clone to a device, image or standard output.
--ignore-fs-check
	Ignore the result of the filesystem consistency check. This option is allowed to be used only with the --metadata option, for the safety of user’s data. The clusters which cause the inconsistency are saved too.
-f, --force
	Forces ntfsclone to proceed if the filesystem is marked "dirty" for consistency check.
-h, --help	Show a list of options with a brief description of each one.

EXIT CODES

The exit code is 0 on success, non-zero otherwise.

EXAMPLES

Save an NTFS to a file in the special image format

ntfsclone --save-image --output backup.img /dev/hda1

Restore an NTFS from a special image file to its original partition

ntfsclone --restore-image --overwrite /dev/hda1 backup.img

Save an NTFS into a compressed image.

ntfsclone --save-image -o - /dev/hda1 | gzip -c > backup.img.gz

Restore an NTFS volume from a compressed image file

gunzip -c backup.img.gz | \\
ntfsclone --restore-image --overwrite /dev/hda1 -

Backup an NTFS volume to a remote host, using ssh.

ntfsclone --save-image --output - /dev/hda1 | \\
gzip -c | ssh host ’cat > backup.img.gz’

Restore an NTFS volume from a remote host via ssh.

ssh host ’cat backup.img.gz’ | gunzip -c | \\
ntfsclone --restore-image --overwrite /dev/hda1 -

Stream an image from a web server and restore it to a partition

wget -qO - http://server/backup.img | \\
ntfsclone --restore-image --overwrite /dev/hda1 -

Clone an NTFS volume to a non-existent file

ntfsclone --output ntfs-clone.img /dev/hda1

Pack NTFS metadata for NTFS experts

ntfsclone --metadata --output ntfsmeta.img /dev/hda1
tar -cjSf ntfsmeta.img.tar.bz2 ntfsmeta.img

KNOWN ISSUES

This program has no known bugs. If you think you have found one then please send an email to linux-ntfs-dev@lists.sourceforge.net

Sometimes it might appear ntfsclone froze if the clone is on ReiserFS and even CTRL-C won’t stop it. This is not a bug in ntfsclone, however it’s due to ReiserFS being extremely inefficient creating large sparse files and not handling signals during this operation. This ReiserFS problem was improved in kernel 2.4.22. XFS, JFS and ext3 don’t have this problem.

AUTHOR

ntfsclone was written by Szabolcs Szakacsits.

Special image format support was added by Per Olofsson.

AVAILABILITY

ntfsclone is part of the ntfsprogs package and is available from
http://linux-ntfs.sourceforge.net

SEE ALSO

ntfsresize(8) ntfsprogs(8) xfs_copy(8) debugreiserfs(8) e2image(8)