The mapper-size plugin provides the `_size` metadata field which, when enabled, indexes the size in bytes of the original [`_source`](/reference/elasticsearch/mapping-reference/mapping-source-field.md) field.
## Installation [mapper-size-install]
This plugin can be installed using the plugin manager:
```sh
sudo bin/elasticsearch-plugin install mapper-size
```
The plugin must be installed on every node in the cluster, and each node must be restarted after installation.
You can download this plugin for [offline install](/reference/elasticsearch-plugins/plugin-management-custom-url.md) from [https://artifacts.elastic.co/downloads/elasticsearch-plugins/mapper-size/mapper-size-{{version}}.zip](https://artifacts.elastic.co/downloads/elasticsearch-plugins/mapper-size/mapper-size-{{version}}.zip). To verify the `.zip` file, use the [SHA hash](https://artifacts.elastic.co/downloads/elasticsearch-plugins/mapper-size/mapper-size-{{version}}.zip.sha512) or [ASC key](https://artifacts.elastic.co/downloads/elasticsearch-plugins/mapper-size/mapper-size-{{version}}.zip.asc).