{
  "id": "mongodb/balancer-round-migration-failure",
  "signature": "MongoServerError: balancer round migration failed: chunk migration failed for namespace mydb.mycoll",
  "signature_zh": "MongoServerError: 均衡器轮次迁移失败：命名空间 mydb.mycoll 的块迁移失败",
  "regex": "balancer round migration failed.*chunk migration failed for namespace",
  "domain": "mongodb",
  "category": "runtime_error",
  "subcategory": null,
  "root_cause": "The balancer failed to migrate a chunk due to a temporary network issue or a conflicting operation on the source or target shard.",
  "root_cause_type": "generic",
  "root_cause_zh": "由于临时网络问题或源/目标分片上的冲突操作，均衡器无法迁移块。",
  "versions": [
    {
      "version": "MongoDB 7.0",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "MongoDB 6.0",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "MongoDB 8.0 (early access)",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "",
      "why_fails": "moveChunk may fail with same error if underlying issue persists, and can disrupt ongoing migrations.",
      "fail_rate": 0.6,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "Stopping balancer is a temporary pause, not a fix; the root cause (e.g., network blip) remains.",
      "fail_rate": 0.7,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "Restart often doesn't resolve underlying connectivity or operation conflicts.",
      "fail_rate": 0.5,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "Check balancer state and retry migration after resolving any conflicting operations (e.g., long-running queries or index builds). Use sh.status() to monitor balancer activity.",
      "success_rate": 0.75,
      "how": "Check balancer state and retry migration after resolving any conflicting operations (e.g., long-running queries or index builds). Use sh.status() to monitor balancer activity.",
      "condition": "",
      "sources": []
    },
    {
      "action": "Increase balancer window or reduce chunk size to make migrations more manageable: use sh.setBalancerState(true) and adjust chunk size via sh._setBalancerChunkSize(64) (in MB).",
      "success_rate": 0.8,
      "how": "Increase balancer window or reduce chunk size to make migrations more manageable: use sh.setBalancerState(true) and adjust chunk size via sh._setBalancerChunkSize(64) (in MB).",
      "condition": "",
      "sources": []
    },
    {
      "action": "Force chunk migration manually using moveChunk with a specific shard key range and wait for completion: sh.moveChunk('mydb.mycoll', { shardKey: value }, 'targetShard').",
      "success_rate": 0.85,
      "how": "Force chunk migration manually using moveChunk with a specific shard key range and wait for completion: sh.moveChunk('mydb.mycoll', { shardKey: value }, 'targetShard').",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [
    "Check balancer state and retry migration after resolving any conflicting operations (e.g., long-running queries or index builds). Use sh.status() to monitor balancer activity.",
    "Increase balancer window or reduce chunk size to make migrations more manageable: use sh.setBalancerState(true) and adjust chunk size via sh._setBalancerChunkSize(64) (in MB).",
    "Force chunk migration manually using moveChunk with a specific shard key range and wait for completion: sh.moveChunk('mydb.mycoll', { shardKey: value }, 'targetShard')."
  ],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": null,
  "official_doc_section": null,
  "error_code": null,
  "verification_tier": "ai_generated",
  "confidence": 0.88,
  "fix_success_rate": 0.85,
  "resolvable": "true",
  "first_seen": "2023-11-15",
  "last_confirmed": "2024-06-01",
  "last_updated": "2024-06-01",
  "evidence_count": 1,
  "tags": [],
  "locale": "en",
  "aliases": []
}