# MinIO Server Config Guide [![Slack](https://slack.min.io/slack?type=svg)](https://slack.min.io) [![Docker Pulls](https://img.shields.io/docker/pulls/minio/minio.svg?maxAge=604800)](https://hub.docker.com/r/minio/minio/)

## Configuration Directory

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).

### Certificate Directory

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).

Following is a sample directory structure for MinIO server with TLS certificates.

```sh
$ mc tree --files ~/.minio
/home/user1/.minio
└─ certs
   ├─ CAs
   ├─ private.key
   └─ public.crt
```

You can provide a custom certs directory using `--certs-dir` command line option.

#### Credentials

On MinIO admin credentials or root credentials are only allowed to be changed using ENVs namely `MINIO_ROOT_USER` and `MINIO_ROOT_PASSWORD`.

```sh
export MINIO_ROOT_USER=minio
export MINIO_ROOT_PASSWORD=minio13
minio server /data
```

#### Site

```
KEY:
site  label the server and its location

ARGS:
name     (string)    name for the site e.g. "cal-rack0"
region   (string)    name of the location of the server e.g. "us-west-1"
comment  (sentence)  optionally add a comment to this setting
```

or environment variables

```
KEY:
site  label the server and its location

ARGS:
MINIO_SITE_NAME     (string)    name for the site e.g. "cal-rack0"
MINIO_SITE_REGION   (string)    name of the location of the server e.g. "us-west-1"
MINIO_SITE_COMMENT  (sentence)  optionally add a comment to this setting
```

Example:

```sh
export MINIO_SITE_REGION="us-west-0"
export MINIO_SITE_NAME="sfo-rack-1"
minio server /data
```

### Storage Class

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).

```
KEY:
storage_class  define object level redundancy

ARGS:
standard  (string)    set the parity count for default standard storage class e.g. "EC:4"
rrs       (string)    set the parity count for reduced redundancy storage class e.g. "EC:2"
comment   (sentence)  optionally add a comment to this setting
```

or environment variables

```
KEY:
storage_class  define object level redundancy

ARGS:
MINIO_STORAGE_CLASS_STANDARD  (string)    set the parity count for default standard storage class e.g. "EC:4"
MINIO_STORAGE_CLASS_RRS       (string)    set the parity count for reduced redundancy storage class e.g. "EC:2"
MINIO_STORAGE_CLASS_COMMENT   (sentence)  optionally add a comment to this setting
```

#### Etcd

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
```

or environment variables

```
KEY:
etcd  federate multiple clusters for IAM and Bucket DNS

ARGS:
MINIO_ETCD_ENDPOINTS*       (csv)       comma separated list of etcd endpoints e.g. "http://localhost:2379"
MINIO_ETCD_PATH_PREFIX      (path)      namespace prefix to isolate tenants e.g. "customer1/"
MINIO_ETCD_COREDNS_PATH     (path)      shared bucket DNS records, default is "/skydns"
MINIO_ETCD_CLIENT_CERT      (path)      client cert for mTLS authentication
MINIO_ETCD_CLIENT_CERT_KEY  (path)      client cert key for mTLS authentication
MINIO_ETCD_COMMENT          (sentence)  optionally add a comment to this setting
```

### API

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).

```
KEY:
api  manage global HTTP API call specific features, such as throttling, authentication types, etc.

ARGS:
requests_max                    (number)    set the maximum number of concurrent requests (default: 'auto')
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", "auto" (default: 'strict')
replication_priority            (string)    set replication priority (default: 'auto')
replication_max_workers         (number)    set the maximum number of replication workers (default: '500')
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 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')
object_max_versions             (number)    set max allowed number of versions per object (default: '9223372036854775807')
```

or environment variables

```
MINIO_API_REQUESTS_MAX                    (number)    set the maximum number of concurrent requests (default: 'auto')
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", "auto" (default: 'strict')
MINIO_API_REPLICATION_PRIORITY            (string)    set replication priority (default: 'auto')
MINIO_API_REPLICATION_MAX_WORKERS         (number)    set the maximum number of replication workers (default: '500')
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 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')
MINIO_API_OBJECT_MAX_VERSIONS             (number)    set max allowed number of versions per object (default: '9223372036854775807')
```

#### Notifications

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).

```
notify_webhook        publish bucket notifications to webhook endpoints
notify_amqp           publish bucket notifications to AMQP endpoints
notify_kafka          publish bucket notifications to Kafka endpoints
notify_mqtt           publish bucket notifications to MQTT endpoints
notify_nats           publish bucket notifications to NATS endpoints
notify_nsq            publish bucket notifications to NSQ endpoints
notify_mysql          publish bucket notifications to MySQL databases
notify_postgres       publish bucket notifications to Postgres databases
notify_elasticsearch  publish bucket notifications to Elasticsearch endpoints
notify_redis          publish bucket notifications to Redis datastores
```

### Accessing configuration

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).

#### List all config keys available

```
~ mc admin config set myminio/
```

#### Obtain help for each key

```
~ mc admin config set myminio/ <key>
```

e.g: `mc admin config set myminio/ etcd` returns available `etcd` config args

```
~ mc admin config set play/ etcd
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
```

To get ENV equivalent for each config args use `--env` flag

```
~ mc admin config set play/ etcd --env
KEY:
etcd  federate multiple clusters for IAM and Bucket DNS

ARGS:
MINIO_ETCD_ENDPOINTS*       (csv)       comma separated list of etcd endpoints e.g. "http://localhost:2379"
MINIO_ETCD_PATH_PREFIX      (path)      namespace prefix to isolate tenants e.g. "customer1/"
MINIO_ETCD_COREDNS_PATH     (path)      shared bucket DNS records, default is "/skydns"
MINIO_ETCD_CLIENT_CERT      (path)      client cert for mTLS authentication
MINIO_ETCD_CLIENT_CERT_KEY  (path)      client cert key for mTLS authentication
MINIO_ETCD_COMMENT          (sentence)  optionally add a comment to this setting
```

This behavior is consistent across all keys; each key self-documents itself with valid examples.

## Dynamic systems without restarting server

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
scanner               manage namespace scanning for usage calculation, lifecycle, healing and more
```

> NOTE: if you set any of the following sub-system configuration using ENVs, dynamic behavior is not supported.

### Usage scanner

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.

```
~ mc admin config set alias/ scanner
KEY:
scanner  manage namespace scanning for usage calculation, lifecycle, healing and more

ARGS:
delay     (float)     scanner delay multiplier, defaults to '10.0'
max_wait  (duration)  maximum wait time between operations, defaults to '15s'
cycle     (duration)  time duration between scanner cycles
```

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.

```sh
~ mc admin config set alias/ scanner delay=30.0
```

Once set the scanner settings are automatically applied without the need for server restarts.

### Healing

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` .


```
~ mc admin config set alias/ heal
KEY:
heal  manage object healing frequency and bitrot verification checks

ARGS:
bitrotscan     (on|off)    perform bitrot scan on drives when checking objects during scanner
max_sleep      (duration)  maximum sleep duration between objects to slow down heal operation. eg. 2s
max_io         (int)       maximum IO requests allowed between objects to slow down heal operation. eg. 3
drive_workers  (int)       the number of workers per drive to heal a new disk replacement.
```

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`.

```sh
~ mc admin config set alias/ heal max_sleep=300ms max_io=100
```

Once set the healer settings are automatically applied without the need for server restarts.

## Environment only settings (not in config)

### Browser

Enable or disable access to console web UI. By default it is set to `on`. You may override this field with `MINIO_BROWSER` environment variable.

Example:

```sh
export MINIO_BROWSER=off
minio server /data
```

### Domain

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).

Example:

```sh
export MINIO_DOMAIN=mydomain.com
minio server /data
```

For advanced use cases `MINIO_DOMAIN` environment variable supports multiple-domains with comma separated values.

```sh
export MINIO_DOMAIN=sub1.mydomain.com,sub2.mydomain.com
minio server /data
```

## Explore Further

* [MinIO Quickstart Guide](https://min.io/docs/minio/linux/index.html#quickstart-for-linux)
* [Configure MinIO Server with TLS](https://min.io/docs/minio/linux/operations/network-encryption.html)
