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Kafka DescribeLogDirs Response Wire Format v1 — Binary Protocol Layout

What is DescribeLogDirs?

Shows per-broker disk usage, replica offset lag, and which replicas are mid-move (futureLogDir), via kafka-log-dirs.sh. High offsetLag on a follower replica indicates it's lagging behind the leader; compare with the ISR list to assess replication health.

Related Errors

CLUSTER_AUTHORIZATION_FAILED · KAFKA_STORAGE_ERROR · NOT_LEADER_OR_FOLLOWER · UNKNOWN_TOPIC_OR_PARTITION

Wire Diagram

Response Header
message_size int32 · 4B
correlation_id int32 · 4B
DescribeLogDirsResponse v1
ThrottleTimeMs int32 · 4B
Results array
ErrorCode int16 · 2B
LogDir string
Topics array
Name string
Partitions array
PartitionIndex int32 · 4B
PartitionSize int64 · 8B
OffsetLag int64 · 8B
IsFutureKey bool · 1B

Schema & Example

Schema
{
  "ThrottleTimeMs": int32,
  "Results": [{
      "ErrorCode": int16,
      "LogDir": string,
      "Topics": [{
          "Name": string,
          "Partitions": [{
              "PartitionIndex": int32,
              "PartitionSize": int64,
              "OffsetLag": int64,
              "IsFutureKey": bool
          }]
      }]
  }]
}
Example
{
  "ThrottleTimeMs": 0,
  "Results": [{
      "ErrorCode": 0,
      "LogDir": "/var/kafka-logs",
      "Topics": [{
          "Name": "orders",
          "Partitions": [{
              "PartitionIndex": 3,
              "PartitionSize": 1048576,
              "OffsetLag": 150382,
              "IsFutureKey": true
          }]
      }]
  }]
}