MinIO server allows streaming compression to ensure efficient disk space usage. Compression happens inflight, i.e objects are compressed before being written to disk(s). MinIO uses [`golang/snappy`](https://github.com/golang/snappy) streaming compression due to its stability and performance.
Compression can be enabled by updating the `compress` config settings for MinIO server config. Config `compress` settings take extensions and mime-types to be compressed.
Since text, log, csv, json files are highly compressible, These extensions/mime-types are included by default for compression.
To update the configuration, use `mc admin config get` command to get the current configuration file for the minio cluster in json format, and save it locally.
After updating the compression configuration in /tmp/myconfig , use `mc admin config set` command to update the configuration for the cluster. Restart the MinIO server to put the changes into effect.
The compression settings may also be set through environment variables. When set, environment variables override the defined `compress` config settings in the server config.
```bash
export MINIO_COMPRESS="true"
export MINIO_COMPRESS_EXTENSIONS=".pdf,.doc"
export MINIO_COMPRESS_MIMETYPES="application/pdf"
```
### 3. Note
- Already compressed objects are not fit for compression since they do not have compressible patterns. Such objects do not produce efficient [`Run-length encoding (RLE)`](https://en.wikipedia.org/wiki/Run-length_encoding) which is a fitness factor for a lossless data compression. Below is a list of common files and content-types which are not suitable for compression.
- MinIO does not support encryption with compression because compression and encryption together enables room for side channel attacks like [`CRIME and BREACH`](https://en.wikipedia.org/wiki/CRIME)
