Admin API v4 Query Endpoints

Admin API v4 provides high-performance query endpoints for cluster introspection. These endpoints return information about cluster topology, nodes, drives, pools, and erasure sets using MessagePack binary encoding for efficient transfer.

All endpoints require valid MinIO AIStor access credentials and the ServerInfoAdminAction authorization policy.

Response format

All query endpoints return binary MessagePack-encoded responses, not JSON. Use the madmin-go v4 client library to decode responses:

import "github.com/minio/madmin-go/v4"

client, err := madmin.New("localhost:9000", "accesskey", "secretkey", false)
cluster, err := client.ClusterQuery(ctx)

Cluster

GET /minio/admin/v4/query/cluster

Returns high-level cluster information including bucket count, object count, capacity, and pool layout.

Key fields:

Mode - Deployment mode (standalone, distributed)
BucketCount, ObjectCount, VersionCount - Object statistics
RawTotalBytes, RawFreeBytes - Raw storage capacity
UsableTotalBytes, UsableFreeBytes - Usable storage capacity
PoolCount, SetCount, NodeCount - Topology counts
OnlineDrives, OfflineDrives - Drive health summary

Services

GET /minio/admin/v4/query/services

Returns status of connected services: LDAP, logger, audit, notifications, and KMS.

Pools

GET /minio/admin/v4/query/pools

Returns information about storage pools with pagination and filtering.

Query parameters:

Parameter	Type	Default	Description
`limit`	integer	100	Results per page
`offset`	integer	0	Pagination offset
`filter`	string	-	Filter expression
`sort`	string	-	Field to sort by
`sortReversed`	boolean	false	Reverse sort order

Key pool resource fields: PoolIndex, StripeSize, TotalSets, WriteQuorum, ReadQuorum, Parity, DriveCount, DrivesOnline, DrivesOffline, NodeCount, RawCapacity, Usage.

Nodes

GET /minio/admin/v4/query/nodes

Returns information about cluster nodes. Supports the same pagination and filter parameters as the pools endpoint, plus:

Parameter	Type	Default	Description
`metrics`	boolean	false	Include node metrics

Key node resource fields: Host, Version, State (online, offline, initializing, restarting), Uptime, TotalDrives, DriveCounts (by state), PoolIndex.

The response includes a ResultsSummary with counts of nodes by state.

Drives

GET /minio/admin/v4/query/drives

Returns information about cluster drives. Supports pagination and filter parameters, plus:

Parameter	Type	Default	Description
`metrics`	boolean	false	Include detailed drive metrics
`smart`	boolean	false	Include S.M.A.R.T. health data
`1m`	boolean	false	Include 1-minute metrics window
`24h`	boolean	false	Include 24-hour statistics

Key drive resource fields: NodeID, SetIndex, PoolIndex, DriveIndex, Endpoint, State (ok, offline, corrupt, missing, faulty, unformatted), Healing, Size, Used, Available, PercentageUsed.

Erasure sets

GET /minio/admin/v4/query/sets

Returns information about erasure sets. Supports the same pagination and filter parameters as the pools endpoint.

Key erasure set resource fields: PoolIndex, SetIndex, DriveCount, OnlineDrives, OfflineDrives, State (ok, warning, critical, unusable), Usage, RawCapacity, ObjectsCount.

Erasure set states:

State	Description
`ok`	All drives healthy
`warning`	Some parity lost but data safe
`critical`	Limited parity remaining
`unusable`	More than parity drives lost

The response includes a ResultsSummary with counts of sets by state.

Filter expressions

The filter parameter supports flexible filtering:

State=ok                       # Only healthy drives
PoolIndex=0                    # Only drives in pool 0
DrivesOnline>0                 # Pools with online drives
RawCapacity>1099511627776      # Large pools (>1TB)

Pagination

For large clusters, use pagination to retrieve results in pages:

GET /minio/admin/v4/query/drives?limit=50&offset=0
GET /minio/admin/v4/query/drives?limit=50&offset=50

Each response includes a Total field indicating the total number of matching results before pagination.