---
title: Changing log compression formats
summary: null
url: >-
  https://www.fastly.com/documentation/guides/integrations/streaming-logs/changing-log-compression-options
---


Fastly's [Real-Time Log Streaming](/guides/integrations/streaming-logs/about-fastlys-realtime-log-streaming-features) feature allows you to specify compression format and options for file-based logging endpoints. These include the [Azure Blob](/guides/integrations/logging-endpoints/object-and-cloud-storage/log-streaming-azure-blob-storage), [FTP](/guides/integrations/logging-endpoints/protocol-based-and-self-hosted/log-streaming-ftp), [Google Cloud Storage](/guides/integrations/logging-endpoints/object-and-cloud-storage/log-streaming-google-cloud-storage), [Kafka](/guides/integrations/logging-endpoints/data-streaming-and-message-queues/log-streaming-kafka), [OpenStack](/guides/integrations/logging-endpoints/object-and-cloud-storage/log-streaming-openstack), [Amazon S3](/guides/integrations/logging-endpoints/object-and-cloud-storage/log-streaming-amazon-s3), [SFTP](/guides/integrations/logging-endpoints/protocol-based-and-self-hosted/log-streaming-sftp), [Digital Ocean](/guides/integrations/logging-endpoints/object-and-cloud-storage/log-streaming-digitalocean-spaces), and [Cloud Files](/guides/integrations/logging-endpoints/object-and-cloud-storage/log-streaming-cloudfiles) logging endpoints.

## Available log compression formats

Although the default is to use no compression, we allow you to choose one of several compression mechanisms:

* **[Zstandard](https://github.com/facebook/zstd)**, a compression algorithm defined by [RFC 8478](https://datatracker.ietf.org/doc/html/rfc8478)
* **[Snappy](https://github.com/google/snappy)**, a compression and decompression library used by many Google products as referenced in the [Snappy compressed format description](https://github.com/google/snappy/blob/a3e012d762a592423ec83717f7d685b594c0e8e3/format_description.txt)
* **[Gzip](https://www.gzip.org)**, a compression utility as defined in [RFC 1952](https://datatracker.ietf.org/doc/html/rfc1952) and [RFC 1951](https://datatracker.ietf.org/doc/html/rfc1951)

## Using a different compression format

<!-- TabbedPanels component: 
<Panel id="fastly-control-panel">

> **IMPORTANT:** If you're using Gzip compression, the Fastly control panel defaults to a Gzip compression level of 3 and can only be changed using the Logging API. If the Gzip compression level has been set to a value other than `3` via an API call, then that level is displayed as a read-only value.

  Follow these instructions to update a file-based logging endpoint's compression format using the Fastly control panel:

  1. <Partial name='step-login' inline />
  1. <Partial name='step-select-service' inline />
  1. <Partial name='step-click-edit' inline />
  1. Click **Logging**.
  1. Click the name of a file-based logging endpoint you want to edit.
  1. Click **Advanced options** near the bottom of the page.
  1. In the **Compression** section, select a compression format for the logging endpoint.

     ![Logging compression options](/img/compression_formats.png)

  1. Click **Update**.
  1. <Partial name='step-activate-deploy' inline />

</Panel>
<Panel id="api" label="API">

You can use the [Logging API](/reference/api/logging/) for any file-based logging endpoint to update the compression format.

  The API provides two fields for specifying log file compression options: `compression_codec` and `gzip_level`.

  * `compression_codec` is a string that specifies the codec used to compress your logs. One of the following:
     * `zstd` Use [Zstandard](https://facebook.github.io/zstd/) compression.
     * `snappy` Use [Snappy](https://github.com/google/snappy) compression.
     * `gzip` Use [Gzip](https://www.gzip.org). Defaults to gzip compression level 3.
  * `gzip_level` is an integer in the range of 0, signifying no compression, to 9, signifying maximum compression.

  > **IMPORTANT:** Use of `compression_codec` is recommended over use of `gzip_level` unless you need to set the gzip compression level to a value other than 3.

  Keep in mind the following with respect to the request payload:

  * Only one of `compression_codec` or `gzip_level` should be included in a request payload. Specifying both will result in an error.
  * If `compression_codec` is set to "gzip", `gzip_level` will default to 3.
  * If `compression_codec` is not specified in the request payload and a non-zero value for `gzip_level` is set, then `compression_codec` will default to "gzip".
  * If neither `compression_codec` nor `gzip_level` is specified in the request, no compression is applied to log files and `compression_codec` will default to `null`.

  For example, to update the compression format for a service's SFTP logging endpoint to use the Snappy compression codec, the curl command would look something like this:

  ```term copy
  $ curl -X PUT -H "Fastly-Key: YOUR_FASTLY_TOKEN"  -H "Accept: application/json" -d "compression_codec=snappy" https://api.fastly.com/service/SU1Z0isxPaozGVKXdv0eY/version/5/logging/sftp/sftp-log
  ```

  To apply gzip compression to an Azure Blob Storage logging endpoint using the `compression_codec` field, the curl command would look like this:

  ```term copy
  $ curl -X PUT -H "Fastly-Key: YOUR_FASTLY_TOKEN"  -H "Accept: application/json" -d "compression_codec=gzip" https://api.fastly.com/service/SU1Z0isxPaozGVKXdv0eY/version/7/logging/azureblob/azure-log
  ```

  To update a Google Cloud Storage logging endpoint's compression format to 1 using the `gzip_level` field, the curl command would look like this:

  ```term copy
  $ curl -X PUT -H "Fastly-Key: YOUR_FASTLY_TOKEN"  -H "Accept: application/json" -d "gzip_level=1" https://api.fastly.com/service/SU1Z0isxPaozGVKXdv0eY/version/4/logging/gcs/gcs-log
  ```

</Panel>
 -->


## Related content

* [Real-time log streaming](/guides/integrations/streaming-logs/about-fastlys-realtime-log-streaming-features)
* [Logging API reference](/reference/api/logging/)
* [Logging CLI reference](/reference/cli/logging/)