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 [`klauspost/compress/s2`](https://github.com/klauspost/compress/tree/master/s2) streaming compression due to its stability and performance.
This algorithm is specifically optimized for machine generated content. Write throughput is typically at least 300MB/s per CPU core. Decompression speed is typically at least 1GB/s.
This means that in cases where raw IO is below these numbers compression will not only reduce disk usage but also help increase system throughput.
Typically enabling compression on spinning disk systems will increase speed when the content can be compressed.
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.
Having compression enabled and no extensions or mime types will attempt to compress anything that isn't explicitly known to be already compressed content.
Settings for enabling compression on all content, except for types listed below:
```json
"compress": {
"enabled": true,
"extensions": [],
"mime-types": []
}
```
Incompressible content will be skipped with quite low CPU usage and storage overhead, typically at several GB/s.
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.
- Already compressed objects are not fit for compression since they do not have compressible patterns. Such objects do not produce efficient [`LZ compression`](https://en.wikipedia.org/wiki/LZ77_and_LZ78) 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 potentially enables room for side channel attacks like [`CRIME and BREACH`](https://blog.minio.io/c-e-compression-encryption-cb6b7f04a369)
