---
name: "cache_writeback"
section: "8"
platform: "linux"
package: "thin-provisioning-tools"
version: "1.3.4-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/cache_writeback"
---

# cache\_writeback(8)

writeback dirty blocks to the origin device.

## NAME

**cache\_writeback** - writeback dirty blocks to the origin device.

## SYNOPSIS

```
cache_writeback [options] --metadata-device {device|file} --origin-device {device|file} --fast-device {device|file}
```

## DESCRIPTION

**cache\_writeback is an offline tool that writes back dirty data to the data** **device (origin). Intended for use in recovery scenarios when the SSD is** **giving IO errors.**

**This tool cannot be run on a live cache.**

## OPTIONS

- **-h, --help**

  **Print help and exit.**

- **-V, --version**

  **Print version information and exit.**

- **--metadata-device {device\|file}**

  **Location of cache metadata.**

- **--origin-device {device\|file}**

  **Slow device being cached.**

- **--fast-device {device\|file}**

  **Fast device containing the data that needs to be written back.**

- **--no-metadata-update**

  **Do not update the metadata to clear the dirty flags.**

```
    You may want to use this flag if you're decommissioning the cache.
```

- **--buffer-size-meg {size}**

  **Specify the size for the data cache, in megabytes.**

```
    Defaults to 64 MiB, a larger size may improve performance.
```

- **--list-failed-blocks**

  **List any blocks that failed the writeback process.**

## SEE ALSO

**[cache\_dump(8)](/cache_dump/8.md), [cache\_check(8)](/cache_check/8.md), [cache\_repair(8)](/cache_repair/8.md), [cache\_restore(8)](/cache_restore/8.md)**

## AUTHOR

**Joe Thornber \<ejt@redhat.com\>**