> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/server/server-usage/storage-engines/innodb/innodb-data-scrubbing.md).

# InnoDB Data Scrubbing

This feature allows for the secure deletion of data by overwriting deleted records in tablespaces and logs to prevent data recovery.

Sometimes there is a requirement that when some data is deleted, it is really gone. This might be the case when one stores user's personal information or some other sensitive data. Normally though, when a row is deleted, the space is only marked as free on the page. It may eventually be overwritten, but there is no guarantee when that will happen. A copy of the deleted rows may also be present in the log files.

Support for [InnoDB](/docs/server/server-usage/storage-engines/innodb.md) data scrubbing: Background threads periodically scan tablespaces and logs and remove all data that should be deleted. The number of background threads for tablespace scans is set by [innodb-encryption-threads](/docs/server/server-usage/storage-engines/innodb/innodb-system-variables.md). Log scrubbing happens in a separate thread.

To configure scrubbing one can use the following variables:

|                                                                                                                                                                  |         |                                        |
| ---------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------- | -------------------------------------- |
| [innodb-immediate-scrub-data-uncompressed](/docs/server/server-usage/storage-engines/innodb/innodb-system-variables.md#innodb_immediate_scrub_data_uncompressed) | Boolean | Enable scrubbing of uncompressed data. |

Redo log scrubbing is not supported ([MDEV-21870](https://jira.mariadb.org/browse/MDEV-21870)). If old log contents should be kept secret, enabling [innodb\_encrypt\_log](/docs/server/server-usage/storage-engines/innodb/innodb-system-variables.md#innodb_encrypt_log) or setting a smaller [innodb\_log\_file\_size](/docs/server/server-usage/storage-engines/innodb/innodb-system-variables.md#innodb_log_file_size) could help.

## Thanks

* Scrubbing was donated to the MariaDB project by Google.

<sub>*This page is licensed: CC BY-SA / Gnu FDL*</sub>

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