#### Key rotation

S3 clients can change the client-provided key of an existing object. Therefore an S3 client must perform a S3 COPY operation where the copy source and destination are equal. Further the COPY request headers must contain the current and the new client key:

- `X-Amz-Server-Side-Encryption-Customer-Key`: Base64 encoded new key.

### Allowed values for STANDARD storage class

`STANDARD` storage class implies more parity than `REDUCED_REDUNDANCY` class. So, `STANDARD` parity drives should be

- Greater than or equal to 2, if `REDUCED_REDUNDANCY` parity is not set.
- Greater than `REDUCED_REDUNDANCY` parity, if it is set.

- **MinIO chooses the largest EC set size which divides into the total number of drives or total number of nodes given - making sure to keep the uniform distribution i.e each node participates equal number of drives per set**.
- **Each object is written to a single EC set, and therefore is spread over no more than 16 drives.**