In metrics version 3, all metrics are available under the endpoint:
```
/minio/metrics/v3
```
however, a specific path under this is required.
Metrics are organized into groups at paths **relative** to the top-level endpoint above.
## Metrics Request Handling
Each endpoint below can be queried at different intervals as needed via a scrape configuration in Prometheus or a compatible metrics collection tool.
For ease of configuration, each (non-empty) parent of the path serves all metric endpoints that are at descendant paths. For example, to query all system metrics one needs to only scrape `/minio/metrics/v3/system/`.
Some metrics are bucket specific. These will have a `/bucket` component in their path. As the number of buckets can be large, the metrics scrape operation needs to be provided with a specific list of buckets via the `bucket` query parameter. Only metrics for the given buckets will be returned (with the bucket label set). For example to query API metrics for buckets `test1` and `test2`, make a scrape request to `/minio/metrics/v3/api/bucket?buckets=test1,test2`.
Instead of a metrics scrape, it is also possible to list the metrics that would be returned by a path. This is done by adding a `?list` query parameter. The MinIO server will then list all possible metrics that could be returned. During an actual metrics scrape, only available metrics are returned - not all of them. With the `list` query parameter, the output format can be selected - just set the request `Content-Type` to `application/json` for JSON output, or `text/plain` for a simple markdown formatted table. The latter is the default.
## Request, System and Cluster Metrics
At a high level metrics are grouped into three categories, listed in the following sub-sections. The path in each of the tables is relative to the top-level endpoint.
### Request metrics
These are metrics about requests served by the (current) node.
| `minio_api_requests_rejected_auth_total` | `counter` | Total number of requests rejected for auth failure | `type,pool_index,server` |
| `minio_api_requests_rejected_header_total` | `counter` | Total number of requests rejected for invalid header | `type,pool_index,server` |
| `minio_api_requests_rejected_timestamp_total` | `counter` | Total number of requests rejected for invalid timestamp | `type,pool_index,server` |
| `minio_api_requests_rejected_invalid_total` | `counter` | Total number of invalid requests | `type,pool_index,server` |
| `minio_api_requests_waiting_total` | `gauge` | Total number of requests in the waiting queue | `type,pool_index,server` |
| `minio_api_requests_incoming_total` | `gauge` | Total number of incoming requests | `type,pool_index,server` |
| `minio_api_requests_inflight_total` | `gauge` | Total number of requests currently in flight | `name,type,pool_index,server` |
| `minio_api_requests_total` | `counter` | Total number of requests | `name,type,pool_index,server` |
| `minio_api_requests_errors_total` | `counter` | Total number of requests with (4xx and 5xx) errors | `name,type,pool_index,server` |
| `minio_api_requests_5xx_errors_total` | `counter` | Total number of requests with 5xx errors | `name,type,pool_index,server` |
| `minio_api_requests_4xx_errors_total` | `counter` | Total number of requests with 4xx errors | `name,type,pool_index,server` |
| `minio_api_requests_canceled_total` | `counter` | Total number of requests canceled by the client | `name,type,pool_index,server` |
| `minio_api_requests_ttfb_seconds_distribution` | `counter` | Distribution of time to first byte across API calls | `name,type,le,pool_index,server` |
| `minio_api_requests_traffic_sent_bytes` | `counter` | Total number of bytes sent | `type,pool_index,server` |
| `minio_api_requests_traffic_received_bytes` | `counter` | Total number of bytes received | `type,pool_index,server` |
| `minio_api_bucket_traffic_received_bytes` | `counter` | Total number of bytes sent for a bucket | `bucket,type,server,pool_index` |
| `minio_api_bucket_traffic_sent_bytes` | `counter` | Total number of bytes received for a bucket | `bucket,type,server,pool_index` |
| `minio_api_bucket_inflight_total` | `gauge` | Total number of requests currently in flight for a bucket | `bucket,name,type,server,pool_index` |
| `minio_api_bucket_total` | `counter` | Total number of requests for a bucket | `bucket,name,type,server,pool_index` |
| `minio_api_bucket_canceled_total` | `counter` | Total number of requests canceled by the client for a bucket | `bucket,name,type,server,pool_index` |
| `minio_api_bucket_4xx_errors_total` | `counter` | Total number of requests with 4xx errors for a bucket | `bucket,name,type,server,pool_index` |
| `minio_api_bucket_5xx_errors_total` | `counter` | Total number of requests with 5xx errors for a bucket | `bucket,name,type,server,pool_index` |
| `minio_api_bucket_ttfb_seconds_distribution` | `counter` | Distribution of time to first byte across API calls for a bucket | `bucket,name,le,type,server,pool_index` |
| `minio_system_drive_availability_errors_total` | `counter` | Total availability errors (I/O errors, timeouts) on a drive | `drive,set_index,drive_index,pool_index,server` |
| `minio_system_drive_waiting_io` | `gauge` | Total waiting I/O operations on a drive | `drive,set_index,drive_index,pool_index,server` |
| `minio_system_drive_api_latency_micros` | `gauge` | Average last minute latency in µs for drive API storage operations | `drive,api,set_index,drive_index,pool_index,server` |
| `locks_read_total` | `gauge` | Number of current READ locks on this peer | `server` |
| `locks_write_total` | `gauge` | Number of current WRITE locks on this peer | `server` |
| `cpu_total_seconds` | `counter` | Total user and system CPU time spent in seconds | `server` |
| `go_routine_total` | `gauge` | Total number of go routines running | `server` |
| `io_rchar_bytes` | `counter` | Total bytes read by the process from the underlying storage system including cache, /proc/[pid]/io rchar | `server` |
| `io_read_bytes` | `counter` | Total bytes read by the process from the underlying storage system, /proc/[pid]/io read_bytes | `server` |
| `io_wchar_bytes` | `counter` | Total bytes written by the process to the underlying storage system including page cache, /proc/[pid]/io wchar | `server` |
| `io_write_bytes` | `counter` | Total bytes written by the process to the underlying storage system, /proc/[pid]/io write_bytes | `server` |
| `start_time_seconds` | `gauge` | Start time for MinIO process in seconds since Unix epoc | `server` |
| `uptime_seconds` | `gauge` | Uptime for MinIO process in seconds | `server` |
| `file_descriptor_limit_total` | `gauge` | Limit on total number of open file descriptors for the MinIO Server process | `server` |
| `file_descriptor_open_total` | `gauge` | Total number of open file descriptors by the MinIO Server process | `server` |
| `syscall_read_total` | `counter` | Total read SysCalls to the kernel. /proc/[pid]/io syscr | `server` |
| `syscall_write_total` | `counter` | Total write SysCalls to the kernel. /proc/[pid]/io syscw | `server` |
| `minio_cluster_notification_current_send_in_progress` | `counter` | Number of concurrent async Send calls active to all targets | |
| `minio_cluster_notification_events_errors_total` | `counter` | Events that were failed to be sent to the targets | |
| `minio_cluster_notification_events_sent_total` | `counter` | Total number of events sent to the targets | |
| `minio_cluster_notification_events_skipped_total` | `counter` | Events that were skipped to be sent to the targets due to the in-memory queue being full | |
| `minio_cluster_iam_last_sync_duration_millis` | `counter` | Last successful IAM data sync duration in milliseconds | |
| `minio_cluster_iam_plugin_authn_service_failed_requests_minute` | `counter` | When plugin authentication is configured, returns failed requests count in the last full minute | |
| `minio_cluster_iam_plugin_authn_service_last_fail_seconds` | `counter` | When plugin authentication is configured, returns time (in seconds) since the last failed request to the service | |
| `minio_cluster_iam_plugin_authn_service_last_succ_seconds` | `counter` | When plugin authentication is configured, returns time (in seconds) since the last successful request to the service | |
| `minio_cluster_iam_plugin_authn_service_succ_avg_rtt_ms_minute` | `counter` | When plugin authentication is configured, returns average round-trip-time of successful requests in the last full minute | |
| `minio_cluster_iam_plugin_authn_service_succ_max_rtt_ms_minute` | `counter` | When plugin authentication is configured, returns maximum round-trip-time of successful requests in the last full minute | |
| `minio_cluster_iam_plugin_authn_service_total_requests_minute` | `counter` | When plugin authentication is configured, returns total requests count in the last full minute | |
| `minio_cluster_iam_since_last_sync_millis` | `counter` | Time (in milliseconds) since last successful IAM data sync | |
| `minio_cluster_iam_sync_failures` | `counter` | Number of failed IAM data syncs since server start | |
| `minio_cluster_iam_sync_successes` | `counter` | Number of successful IAM data syncs since server start | |