```

### 3.2 Automatic removal of noncurrent versions keeping only most recent ones after noncurrent days

It is possible to configure automatic removal of older noncurrent versions keeping only the most recent `N` using `NewerNoncurrentVersions`.

e.g, To remove noncurrent versions of all objects keeping the most recent 5 noncurrent versions under the prefix `user-uploads/` 30 days after they become noncurrent ,

```

updates being reflected. The delays between each operation of the scanner can be adjusted by the `mc admin config set alias/ delay=15.0`. By default the value is `10.0`. This means the scanner will sleep *10x* the time each operation takes.

In most setups this will keep the scanner slow enough to not impact overall system performance. Setting the `delay` key to a *lower* value will make the scanner faster and setting it to 0 will make the scanner run at full speed (not recommended in production)....

                                                                └─────────┘
```

In a given setup, there are `n` MinIO instances talking to `m` KES servers but only `1` central KMS. The most simple setup consists of `1` MinIO server or cluster talking to `1` KMS via `1` KES server.

```

Let's take for example a set of 12 compute nodes with an aggregate memory of _1.2TiB_, we need to do following settings for optimal results. Add the following optimal entries for _core-site.xml_ to configure _s3a_ with **MinIO**. Most important options here are

```
cat ${HADOOP_CONF_DIR}/core-site.xml | kv-pairify | grep "mapred"

mapred.maxthreads.generate.mapoutput=2 # Num threads to write map outputs

#### Rationale

- SSE-C requires application to remember the keys for all GET/PUT operations, any unfortunate loss of keys would automatically mean the objects cannot be accessed anymore.
- SSE-C is hardly adopted by most widely used applications, applications prefer server to manage the keys via SSE-KMS or SSE-S3.
- MinIO recommends applications to use SSE-KMS, SSE-S3 for simpler, safer and robust encryption mechanism for replicated buckets.

[Using boto3](https://github.com/minio/minio/blob/master/docs/extensions/s3zip/examples/boto3/main.py)

## Requirements and limits

- ListObjectsV2 can only list the most recent ZIP archive version of your object, applicable only for versioned buckets.
- ListObjectsV2 API calls must be used to list zip file content.
- Range requests for GetObject/HeadObject for individual files from zip is not supported.

```bash
~ mc admin config get myminio compression
compression extensions=".txt,.log,.csv,.json,.tar,.xml,.bin" mime_types="text/*,application/json,application/xml"
```

Default config includes most common highly compressible content extensions and mime-types.

```bash
~ mc admin config set myminio compression extensions=".pdf" mime_types="application/pdf"
```

To show help on setting compression config values.