{
    "mode": "man",
    "parameter": "cache_writeback",
    "section": "8",
    "url": "https://www.chedong.com/phpMan.php/man/cache_writeback/8/json",
    "generated": "2026-05-30T10:07:51Z",
    "synopsis": "cachewriteback [options] --metadata-device {device|file} --origin-device {device|file} --fast-device {device|file}",
    "sections": {
        "NAME": {
            "content": "cachewriteback - writeback dirty blocks to the origin device.\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "cachewriteback [options] --metadata-device {device|file} --origin-device {device|file} --fast-device {device|file}\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "cachewriteback  is  an offline tool that writes back dirty data to the data device (origin).\nIntended for use in recovery scenarios when the SSD is giving IO errors.\n\nThis tool cannot be run on a live cache.\n",
            "subsections": []
        },
        "OPTIONS": {
            "content": "",
            "subsections": [
                {
                    "name": "-h, --help",
                    "content": "Print help and exit.\n",
                    "flag": "-h",
                    "long": "--help"
                },
                {
                    "name": "-V, --version",
                    "content": "Print version information and exit.\n",
                    "flag": "-V",
                    "long": "--version"
                },
                {
                    "name": "--metadata-device {device|file}",
                    "content": "Location of cache metadata.\n",
                    "long": "--metadata-device"
                },
                {
                    "name": "--origin-device {device|file}",
                    "content": "Slow device being cached.\n",
                    "long": "--origin-device"
                },
                {
                    "name": "--fast-device {device|file}",
                    "content": "Fast device containing the data that needs to be written back.\n",
                    "long": "--fast-device"
                },
                {
                    "name": "--no-metadata-update",
                    "content": "Do not update the metadata to clear the dirty flags.\n\nYou may want to use this flag if you're decommissioning the cache.\n\n",
                    "long": "--no-metadata-update"
                },
                {
                    "name": "--buffer-size-meg {size}",
                    "content": "Specify the size for the metadata cache.\n\nDefaults to 16 Gig, a larger size may improve performance.\n\n",
                    "long": "--buffer-size-meg"
                },
                {
                    "name": "--list-failed-blocks",
                    "content": "List any blocks that failed the writeback process.\n",
                    "long": "--list-failed-blocks"
                }
            ]
        },
        "SEE ALSO": {
            "content": "cachedump(8), cachecheck(8), cacherepair(8), cacherestore(8)\n",
            "subsections": []
        },
        "AUTHOR": {
            "content": "Joe Thornber <ejt@redhat.com>\n\n\n\nSystem Manager's Manual                  Device Mapper Tools                      cachewriteback(8)",
            "subsections": []
        }
    },
    "summary": "cachewriteback - writeback dirty blocks to the origin device.",
    "flags": [
        {
            "flag": "-h",
            "long": "--help",
            "arg": null,
            "description": "Print help and exit."
        },
        {
            "flag": "-V",
            "long": "--version",
            "arg": null,
            "description": "Print version information and exit."
        },
        {
            "flag": "",
            "long": "--metadata-device",
            "arg": null,
            "description": "Location of cache metadata."
        },
        {
            "flag": "",
            "long": "--origin-device",
            "arg": null,
            "description": "Slow device being cached."
        },
        {
            "flag": "",
            "long": "--fast-device",
            "arg": null,
            "description": "Fast device containing the data that needs to be written back."
        },
        {
            "flag": "",
            "long": "--no-metadata-update",
            "arg": null,
            "description": "Do not update the metadata to clear the dirty flags. You may want to use this flag if you're decommissioning the cache."
        },
        {
            "flag": "",
            "long": "--buffer-size-meg",
            "arg": null,
            "description": "Specify the size for the metadata cache. Defaults to 16 Gig, a larger size may improve performance."
        },
        {
            "flag": "",
            "long": "--list-failed-blocks",
            "arg": null,
            "description": "List any blocks that failed the writeback process."
        }
    ],
    "examples": [],
    "see_also": [
        {
            "name": "cachedump",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/cachedump/8/json"
        },
        {
            "name": "cachecheck",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/cachecheck/8/json"
        },
        {
            "name": "cacherepair",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/cacherepair/8/json"
        },
        {
            "name": "cacherestore",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/cacherestore/8/json"
        }
    ]
}