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MinIO Server Config Guide 
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.
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.
Following is a sample directory structure for MinIO server with TLS certificates.
$ 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.
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:
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.
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.
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.
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: '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')
or environment variables
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')
Notifications
Notification targets supported by MinIO are in the following list. To configure individual targets please refer to more detailed documentation here.
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.
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.
~ 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.
~ 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:
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.
Example:
export MINIO_DOMAIN=mydomain.com
minio server /data
For advanced use cases MINIO_DOMAIN environment variable supports multiple-domains with comma separated values.
export MINIO_DOMAIN=sub1.mydomain.com,sub2.mydomain.com
minio server /data