MinIO stores all its config as part of the server deployment, config is erasure coded on MinIO. On a fresh deployment MinIO automatically generates a new `config` and this config is available to be configured via `mc admin config` command. MinIO also encrypts all the config, IAM and policies content if KMS is configured. Please refer to how to encrypt your config and IAM credentials [here](https://github.com/minio/minio/blob/master/docs/kms/IAM.md).
TLS certificates by default are expected to be stored under ``${HOME}/.minio/certs`` directory. You need to place certificates here to enable `HTTPS` based access. Read more about [How to secure access to MinIO server with TLS](https://min.io/docs/minio/linux/operations/network-encryption.html).
By default, parity for objects with standard storage class is set to `N/2`, and parity for objects with reduced redundancy storage class objects is set to `2`. Read more about storage class support in MinIO server [here](https://github.com/minio/minio/blob/master/docs/erasure/storage-class/README.md).
MinIO supports storing encrypted IAM assets in etcd, if KMS is configured. Please refer to how to encrypt your config and IAM credentials [here](https://github.com/minio/minio/blob/master/docs/kms/IAM.md).
> NOTE: if *path_prefix* is set then MinIO will not federate your buckets, namespaced IAM assets are assumed as isolated tenants, only buckets are considered globally unique but performing a lookup with a *bucket* which belongs to a different tenant will fail unlike federated setups where MinIO would port-forward and route the request to relevant cluster accordingly. This is a special feature, federated deployments should not need to set *path_prefix*.
```
KEY:
etcd federate multiple clusters for IAM and Bucket DNS
ARGS:
endpoints* (csv) comma separated list of etcd endpoints e.g. "http://localhost:2379"
path_prefix (path) namespace prefix to isolate tenants e.g. "customer1/"
coredns_path (path) shared bucket DNS records, default is "/skydns"
client_cert (path) client cert for mTLS authentication
client_cert_key (path) client cert key for mTLS authentication
comment (sentence) optionally add a comment to this setting
By default, there is no limitation on the number of concurrent requests that a server/cluster processes at the same time. However, it is possible to impose such limitation using the API subsystem. Read more about throttling limitation in MinIO server [here](https://github.com/minio/minio/blob/master/docs/throttle/README.md).
requests_max (number) set the maximum number of concurrent requests (default: '0')
requests_deadline (duration) set the deadline for API requests waiting to be processed (default: '10s')
cluster_deadline (duration) set the deadline for cluster readiness check (default: '10s')
cors_allow_origin (csv) set comma separated list of origins allowed for CORS requests (default: '*')
remote_transport_deadline (duration) set the deadline for API requests on remote transports while proxying between federated instances e.g. "2h" (default: '2h')
list_quorum (string) set the acceptable quorum expected for list operations e.g. "optimal", "reduced", "disk", "strict" (default: 'strict')
replication_priority (string) set replication priority (default: 'auto')
transition_workers (number) set the number of transition workers (default: '100')
stale_uploads_expiry (duration) set to expire stale multipart uploads older than this values (default: '24h')
stale_uploads_cleanup_interval (duration) set to change intervals when stale multipart uploads are expired (default: '6h')
delete_cleanup_interval (duration) set to change intervals when deleted objects are permanently deleted from ".trash" folder (default: '5m')
odirect (boolean) set to enable or disable O_DIRECT for read and writes under special conditions. NOTE: do not disable O_DIRECT without prior testing (default: 'on')
root_access (boolean) turn 'off' root credential access for all API calls including s3, admin operations (default: 'on')
sync_events (boolean) set to enable synchronous bucket notifications (default: 'off')
MINIO_API_REQUESTS_MAX (number) set the maximum number of concurrent requests (default: '0')
MINIO_API_REQUESTS_DEADLINE (duration) set the deadline for API requests waiting to be processed (default: '10s')
MINIO_API_CLUSTER_DEADLINE (duration) set the deadline for cluster readiness check (default: '10s')
MINIO_API_CORS_ALLOW_ORIGIN (csv) set comma separated list of origins allowed for CORS requests (default: '*')
MINIO_API_REMOTE_TRANSPORT_DEADLINE (duration) set the deadline for API requests on remote transports while proxying between federated instances e.g. "2h" (default: '2h')
MINIO_API_LIST_QUORUM (string) set the acceptable quorum expected for list operations e.g. "optimal", "reduced", "disk", "strict" (default: 'strict')
MINIO_API_REPLICATION_PRIORITY (string) set replication priority (default: 'auto')
MINIO_API_TRANSITION_WORKERS (number) set the number of transition workers (default: '100')
MINIO_API_STALE_UPLOADS_EXPIRY (duration) set to expire stale multipart uploads older than this values (default: '24h')
MINIO_API_STALE_UPLOADS_CLEANUP_INTERVAL (duration) set to change intervals when stale multipart uploads are expired (default: '6h')
MINIO_API_DELETE_CLEANUP_INTERVAL (duration) set to change intervals when deleted objects are permanently deleted from ".trash" folder (default: '5m')
MINIO_API_ODIRECT (boolean) set to enable or disable O_DIRECT for read and writes under special conditions. NOTE: do not disable O_DIRECT without prior testing (default: 'on')
MINIO_API_ROOT_ACCESS (boolean) turn 'off' root credential access for all API calls including s3, admin operations (default: 'on')
MINIO_API_SYNC_EVENTS (boolean) set to enable synchronous bucket notifications (default: 'off')
Notification targets supported by MinIO are in the following list. To configure individual targets please refer to more detailed documentation [here](https://min.io/docs/minio/linux/administration/monitoring.html#bucket-notifications).
All configuration changes can be made using [`mc admin config` get/set/reset/export/import commands](https://github.com/minio/mc/blob/master/docs/minio-admin-complete-guide.md).
The following sub-systems are dynamic i.e., configuration parameters for each sub-systems can be changed while the server is running without any restarts.
```
api manage global HTTP API call specific features, such as throttling, authentication types, etc.
heal manage object healing frequency and bitrot verification checks
Data usage scanner is enabled by default. The following configuration settings allow for more staggered delay in terms of usage calculation. The scanner adapts to the system speed and completely pauses when the system is under load. It is possible to adjust the speed of the scanner and thereby the latency of 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). Setting it to a higher value will make the scanner slower, consuming less resources with the trade off of not collecting metrics for operations like healing and disk usage as fast.
Example: the following setting will decrease the scanner speed by a factor of 3, reducing the system resource use, but increasing the latency of updates being reflected.
Healing is enabled by default. The following configuration settings allow for more staggered delay in terms of healing. The healing system by default adapts to the system speed and pauses up to '250ms' per object when the system has `max_io` number of concurrent requests. It is possible to adjust the `max_sleep` and `max_io` values thereby increasing the healing speed. The delays between each operation of the healer can be adjusted by the `mc admin config set alias/ heal max_sleep=1s` and maximum concurrent requests allowed before we start slowing things down can be configured with `mc admin config set alias/ heal max_io=30` . By default the wait delay is `250ms` beyond 100 concurrent operations. This means the healer will sleep *250 milliseconds* at max for each heal operation if there are more than *100* concurrent client requests.
In most setups this is sufficient to heal the content after drive replacements. Setting `max_sleep` to a *lower* value and setting `max_io` to a *higher* value would make heal go faster.
Each node is responsible of healing its local drives; Each drive will have multiple heal workers which is the quarter of the number of CPU cores of the node or the quarter of the configured nr_requests of the drive (https://www.kernel.org/doc/Documentation/block/queue-sysfs.txt). It is also possible to provide a custom number of workers by using this command: `mc admin config set alias/ heal drive_workers=100` .
Example: The following settings will increase the heal operation speed by allowing healing operation to run without delay up to `100` concurrent requests, and the maximum delay between each heal operation is set to `300ms`.
By default, MinIO supports path-style requests that are of the format <http://mydomain.com/bucket/object>. `MINIO_DOMAIN` environment variable is used to enable virtual-host-style requests. If the request `Host` header matches with `(.+).mydomain.com` then the matched pattern `$1` is used as bucket and the path is used as object. Read more about path-style and virtual-host-style [here](http://docs.aws.amazon.com/AmazonS3/latest/dev/RESTAPI.html).
