{
    "mode": "man",
    "parameter": "fsfreeze",
    "section": "8",
    "url": "https://www.chedong.com/phpMan.php/man/fsfreeze/8/json",
    "generated": "2026-05-30T10:09:03Z",
    "synopsis": "fsfreeze --freeze|--unfreeze mountpoint",
    "sections": {
        "NAME": {
            "content": "fsfreeze - suspend access to a filesystem (Ext3/4, ReiserFS, JFS, XFS)\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "fsfreeze --freeze|--unfreeze mountpoint\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "fsfreeze suspends or resumes access to a filesystem.\n\nfsfreeze halts any new access to the filesystem and creates a stable image on disk. fsfreeze\nis intended to be used with hardware RAID devices that support the creation of snapshots.\n\nfsfreeze is unnecessary for device-mapper devices. The device-mapper (and LVM) automatically\nfreezes a filesystem on the device when a snapshot creation is requested. For more details\nsee the dmsetup(8) man page.\n\nThe mountpoint argument is the pathname of the directory where the filesystem is mounted. The\nfilesystem must be mounted to be frozen (see mount(8)).\n\nNote that access-time updates are also suspended if the filesystem is mounted with the\ntraditional atime behavior (mount option strictatime, for more details see mount(8)).\n",
            "subsections": []
        },
        "OPTIONS": {
            "content": "",
            "subsections": [
                {
                    "name": "-f --freeze",
                    "content": "This option requests the specified a filesystem to be frozen from new modifications. When\nthis is selected, all ongoing transactions in the filesystem are allowed to complete, new\nwrite system calls are halted, other calls which modify the filesystem are halted, and\nall dirty data, metadata, and log information are written to disk. Any process attempting\nto write to the frozen filesystem will block waiting for the filesystem to be unfrozen.\n\nNote that even after freezing, the on-disk filesystem can contain information on files\nthat are still in the process of unlinking. These files will not be unlinked until the\nfilesystem is unfrozen or a clean mount of the snapshot is complete.\n",
                    "flag": "-f",
                    "long": "--freeze"
                },
                {
                    "name": "-u --unfreeze",
                    "content": "This option is used to un-freeze the filesystem and allow operations to continue. Any\nfilesystem modifications that were blocked by the freeze are unblocked and allowed to\ncomplete.\n",
                    "flag": "-u",
                    "long": "--unfreeze"
                },
                {
                    "name": "-V --version",
                    "content": "Display version information and exit.\n",
                    "flag": "-V",
                    "long": "--version"
                },
                {
                    "name": "-h --help",
                    "content": "Display help text and exit.\n",
                    "flag": "-h",
                    "long": "--help"
                }
            ]
        },
        "FILESYSTEM SUPPORT": {
            "content": "This command will work only if filesystem supports has support for freezing. List of these\nfilesystems include (2016-12-18) btrfs, ext2/3/4, f2fs, jfs, nilfs2, reiserfs, and xfs.\nPrevious list may be incomplete, as more filesystems get support. If in doubt easiest way to\nknow if a filesystem has support is create a small loopback mount and test freezing it.\n",
            "subsections": []
        },
        "NOTES": {
            "content": "This man page is based on xfsfreeze(8).\n",
            "subsections": []
        },
        "AUTHORS": {
            "content": "Written by Hajime Taira.\n",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "mount(8)\n",
            "subsections": []
        },
        "REPORTING BUGS": {
            "content": "For bug reports, use the issue tracker at https://github.com/karelzak/util-linux/issues.\n",
            "subsections": []
        },
        "AVAILABILITY": {
            "content": "The fsfreeze command is part of the util-linux package which can be downloaded from Linux\nKernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.\n\n\n\nutil-linux 2.37.2                            2021-06-02                                  FSFREEZE(8)",
            "subsections": []
        }
    },
    "summary": "fsfreeze - suspend access to a filesystem (Ext3/4, ReiserFS, JFS, XFS)",
    "flags": [
        {
            "flag": "-f",
            "long": "--freeze",
            "arg": null,
            "description": "This option requests the specified a filesystem to be frozen from new modifications. When this is selected, all ongoing transactions in the filesystem are allowed to complete, new write system calls are halted, other calls which modify the filesystem are halted, and all dirty data, metadata, and log information are written to disk. Any process attempting to write to the frozen filesystem will block waiting for the filesystem to be unfrozen. Note that even after freezing, the on-disk filesystem can contain information on files that are still in the process of unlinking. These files will not be unlinked until the filesystem is unfrozen or a clean mount of the snapshot is complete."
        },
        {
            "flag": "-u",
            "long": "--unfreeze",
            "arg": null,
            "description": "This option is used to un-freeze the filesystem and allow operations to continue. Any filesystem modifications that were blocked by the freeze are unblocked and allowed to complete."
        },
        {
            "flag": "-V",
            "long": "--version",
            "arg": null,
            "description": "Display version information and exit."
        },
        {
            "flag": "-h",
            "long": "--help",
            "arg": null,
            "description": "Display help text and exit."
        }
    ],
    "examples": [],
    "see_also": [
        {
            "name": "mount",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/mount/8/json"
        }
    ]
}