cryptsetup-resize(8) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | REPORTING BUGS | SEE ALSO | CRYPTSETUP

CRYPTSETUP-RESIZE(8)       Maintenance Commands      CRYPTSETUP-RESIZE(8)

NAME         top

       cryptsetup-resize - resize an active mapping

SYNOPSIS         top

       cryptsetup resize [<options>] <name>

DESCRIPTION         top

       Resizes an active mapping <name>.

       If --size (in 512-byte sectors) or --device-size is not specified,
       the size is computed from the underlying device. For LUKS, it is
       the size of the underlying device without the area reserved for
       the LUKS header (see data payload offset in the luksDump command).
       For a plain crypt device, the whole device size is used.

       Note that this does not change the raw device geometry; it just
       changes how many sectors of the raw device are represented in the
       mapped device.

       If cryptsetup detected a volume key for the active device loaded
       in the kernel keyring service, the resize action would first try
       to retrieve the key using a token. Only if it failed, it’d ask for
       a passphrase to unlock a keyslot (LUKS) or to derive a volume key
       again (plain mode). The kernel keyring is used by default for
       LUKS2 devices.

       <options> can be [--size, --device-size, --token-id, --token-only,
       --token-type, --key-slot, --key-file, --keyfile-size,
       --keyfile-offset, --timeout, --disable-external-tokens,
       --disable-locks, --disable-keyring, --volume-key-keyring,
       --verify-passphrase, --timeout, --external-tokens-path].

OPTIONS         top

       --batch-mode, -q
           Suppresses all confirmation questions. Use with care!

           If the --verify-passphrase option is not specified, this
           option also switches off the passphrase verification.

       --debug or --debug-json
           Run in debug mode with full diagnostic logs. Debug output
           lines are always prefixed by #.

           If --debug-json is used, additional LUKS2 JSON data structures
           are printed.

       --device-size size[units]
           Sets the new size of the device. If unset, the real device
           size is used.

           If no unit suffix is specified, the size is in bytes.

           Unit suffix can be S for 512 byte sectors, K/M/G/T (or KiB,
           MiB, GiB, TiB) for units with 1024 base or KB/MB/GB/TB for
           1000 base (SI scale).

       --disable-external-tokens
           Disable loading of plugins for external LUKS2 tokens.

       --disable-keyring
           Do not load the volume key in the kernel keyring; store it
           directly in the dm-crypt target instead. This option is
           supported only for the LUKS2 type.

       --disable-locks
           Disable lock protection for metadata on disk. This option is
           valid only for LUKS2 and is ignored for other formats.

           WARNING: Do not use this option unless you run cryptsetup in a
           restricted environment where locking is impossible to perform
           (where /run directory cannot be used).

       --external-tokens-path <absolute path>
           Override the system directory path where cryptsetup searches
           for external token handlers (or token plugins). It must be an
           absolute path (starting with '/' character).

       --header <device or file storing the LUKS header>
           Use a detached (separated) metadata device or file where the
           LUKS header is stored. This option allows one to store the
           ciphertext and LUKS header on different devices.

           For commands that change the LUKS header (e.g., luksAddKey),
           specify the device or file with the LUKS header directly as
           the LUKS device.

       --help, -?
           Show help text and default parameters.

       --key-description text
           Set the key description in the keyring that will be used for
           passphrase retrieval.

       --key-file, -d file
           Read the passphrase from the file.

           If the name given is "-", then the passphrase will be read
           from stdin. In this case, reading will not stop at newline
           characters.

           See section NOTES ON PASSPHRASE PROCESSING in cryptsetup(8)
           for more information.

       --keyfile-offset value
           Skip value bytes at the beginning of the key file.

       --keyfile-size, -l value
           Read a maximum of value bytes from the key file. The default
           is to read the whole file up to the compiled-in maximum that
           can be queried with --help. Supplying more data than the
           compiled-in maximum aborts the operation.

           This option is useful to cut trailing newlines, for example.
           If --keyfile-offset is also given, the size count starts after
           the offset.

       --key-slot, -S <0-N>
           For LUKS operations that add key material, this option allows
           you to specify which keyslot is selected for the new key.

           The maximum number of keyslots depends on the LUKS version.
           LUKS1 can have up to 8 keyslots. LUKS2 can have up to 32
           keyslots based on keyslot area size and key size, but a valid
           keyslot ID can always be between 0 and 31 for LUKS2.

       --size, -b <number of 512 byte sectors>
           Set the size of the device in sectors of 512 bytes.

       --timeout, -t seconds
           The number of seconds to wait before a timeout on passphrase
           input via terminal. It is relevant every time a passphrase is
           asked. It has no effect if used in conjunction with
           --key-file.

           This option is useful when the system should not stall if the
           user does not input a passphrase, e.g., during boot. The
           default is a value of 0 seconds, which means to wait forever.

       --token-id
           Specify what token to use and allow the token PIN prompt to
           take precedence over the interactive keyslot passphrase
           prompt. If omitted, all available tokens (not protected by
           PIN) will be checked before proceeding further with the
           passphrase prompt.

       --token-only
           Do not proceed further with the action if the token-based
           keyslot unlock failed. Without the option, the action asks for
           a passphrase to proceed further.

           It allows LUKS2 tokens protected by PIN to take precedence
           over the interactive keyslot passphrase prompt.

       --token-type type
           Restrict tokens eligible for operation to a specific token
           type. Mostly useful when no --token-id is specified.

           It allows LUKS2 type tokens protected by PIN to take
           precedence over the interactive keyslot passphrase prompt.

       --usage
           Show short option help.

       --verify-passphrase, -y
           When interactively asking for a passphrase, ask for it twice
           and complain if both inputs do not match. Ignored on input
           from file or stdin.

       --version, -V
           Show the program version.

       --volume-key-keyring <key description>
           Use a volume key stored in a keyring. This allows one to open
           luks and plain device types without giving a passphrase.

           For LUKS, the key and associated type have to be readable from
           userspace so that the volume key digest may be verified before
           activation. For devices in reencryption, the option may be
           used twice to specify both old and new volume keys.

           For PLAIN type, the user must ensure that the key in the
           keyring is unchanged since activation. Otherwise, reloading
           the key can cause data corruption after an unexpected key
           change.

           The <key description> uses keyctl-compatible syntax. This can
           either be a numeric key ID or a string name in the format
           %<key type>:<key name>. See also the KEY IDENTIFIERS section
           of keyctl(1). When no %<key type>: prefix is specified, we
           assume the key type is user (default type).

REPORTING BUGS         top

       Report bugs at cryptsetup mailing list
       <cryptsetup@lists.linux.dev> or in Issues project section
       <https://gitlab.com/cryptsetup/cryptsetup/-/issues/new>.

       Please attach the output of the failed command with --debug option
       added.

SEE ALSO         top

       Cryptsetup FAQ
       <https://gitlab.com/cryptsetup/cryptsetup/wikis/FrequentlyAskedQuestions>

       cryptsetup(8), integritysetup(8) and veritysetup(8)

CRYPTSETUP         top

       Part of cryptsetup project
       <https://gitlab.com/cryptsetup/cryptsetup/>. This page is part of
       the Cryptsetup ((open-source disk encryption)) project.
       Information about the project can be found at 
       ⟨https://gitlab.com/cryptsetup/cryptsetup⟩. If you have a bug
       report for this manual page, send it to dm-crypt@saout.de. This
       page was obtained from the project's upstream Git repository
       ⟨https://gitlab.com/cryptsetup/cryptsetup.git⟩ on 2025-08-11. (At
       that time, the date of the most recent commit that was found in
       the repository was 2025-08-01.) If you discover any rendering
       problems in this HTML version of the page, or you believe there is
       a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

cryptsetup 2.8.1-git            2025-08-09           CRYPTSETUP-RESIZE(8)

Pages that refer to this page: cryptsetup(8)