# Enforcing storage engine

*Percona Server for MySQL* has implemented variable which can be used for enforcing the
use of a specific storage engine.

When this variable is specified and a user tries to create a table using an
explicit storage engine that is not the specified enforced engine, the user
will get either an error if the `NO_ENGINE_SUBSTITUTION` SQL mode is enabled
or a warning if `NO_ENGINE_SUBSTITUTION` is disabled and the table
will be created anyway using the enforced engine (this is consistent with the
default *MySQL* way of creating the default storage engine if other engines
are not available unless `NO_ENGINE_SUBSTITUTION` is set).

In case user tries to enable [enforce_storage_engine](#enforce_storage_engine) with engine that isn’t available, system will not start.

!!! note

    If you’re using enforce_storage_engine, you must either disable
    it before doing `mysql_upgrade` or perform `mysql_upgrade` with server
    started with `--skip-grants-tables`.

## Version specific information

* [Percona Server for MySQL 8.0.13-4](../release-notes/Percona-Server-8.0.13-4.md#id1): The feature was ported from *Percona Server for MySQL* 5.7.

## System variables

### `enforce_storage_engine`

| Option         | Description        |
| -------------- | ------------------ |
| Command Line:  | Yes                |
| Config file    | Yes                |
| Scope:         | Global             |
| Dynamic:       | No                 |
| Data type      | String             |
| Default value  | NULL               |

This variable is not case sensitive.

## Example

Adding following option to [my.cnf](../glossary.md#my.cnf) will start the server with InnoDB as enforced storage engine.

```text
enforce_storage_engine=InnoDB
```