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3rd chunk of `content/manuals/engine/logging/dual-logging.md`
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[`local` logging driver](drivers/local.md), but with a `cache-` prefix. These options
can be specified per container, and defaults for new containers can be set using
the [daemon configuration file](/reference/cli/dockerd/#daemon-configuration-file).

By default, the cache has log-file rotation enabled, and is limited to a maximum
of 5 files of 20MB each (before compression) per container. Use the configuration
options described below to customize these defaults.

| Option           | Default   | Description                                                                                                                                       |
| :--------------- | :-------- | :------------------------------------------------------------------------------------------------------------------------------------------------ |
| `cache-disabled` | `"false"` | Disable local caching. Boolean value passed as a string (`true`, `1`, `0`, or `false`).                                                           |
| `cache-max-size` | `"20m"`   | The maximum size of the cache before it is rotated. A positive integer plus a modifier representing the unit of measure (`k`, `m`, or `g`).       |
| `cache-max-file` | `"5"`     | The maximum number of cache files that can be present. If rotating the logs creates excess files, the oldest file is removed. A positive integer. |
| `cache-compress` | `"true"`  | Enable or disable compression of rotated log files. Boolean value passed as a string (`true`, `1`, `0`, or `false`).                              |

## Disable the dual logging cache

Use the `cache-disabled` option to disable the dual logging cache. Disabling the
cache can be useful to save storage space in situations where logs are only read
through a remote logging system, and if there is no need to read logs through
`docker logs` for debugging purposes.

Caching can be disabled for individual containers or by default for new containers,
when using the [daemon configuration file](/reference/cli/dockerd/#daemon-configuration-file).

The following example uses the daemon configuration file to use the [`splunk`](drivers/splunk.md)
logging driver as a default, with caching disabled:

```console
$ cat /etc/docker/daemon.json
{
  "log-driver": "splunk",
  "log-opts": {
    "cache-disabled": "true",
    ... (options for "splunk" logging driver)
  }
}
```

> [!NOTE]
>
> For logging drivers that support reading logs, such as the `local`, `json-file`
> and `journald` drivers, dual logging isn't used, and disabling the option has
> no effect.

## Limitations

- If a container using a logging driver or plugin that sends logs remotely
  has a network issue, no `write` to the local cache occurs.
- If a write to `logdriver` fails for any reason (file system full, write
  permissions removed), the cache write fails and is logged in the daemon log.
  The log entry to the cache isn't retried.
- Some logs might be lost from the cache in the default configuration because a
  ring buffer is used to prevent blocking the stdio of the container in case of
  slow file writes. An admin must repair these while the daemon is shut down.
Title: Dual Logging Cache Options, Disabling, and Limitations
Summary
This section details configuration options for the dual logging cache, including disabling it with `cache-disabled`, setting maximum size and file count with `cache-max-size` and `cache-max-file`, and enabling compression with `cache-compress`. It explains how to disable the cache to save storage when logs are read remotely and not via `docker logs`. The section provides an example of disabling the cache in the daemon configuration file when using the Splunk driver. Finally, it outlines limitations of the dual logging system, such as issues with network connectivity, write failures, and potential log loss due to the ring buffer.