{
  "id": "mongodb/balancer-failed-to-move-chunk",
  "signature": "MongoServerError: balancer failed to move chunk: chunk { ns: \"test.users\", min: { _id: 1 }, max: { _id: 100 } } could not be moved",
  "signature_zh": "MongoServerError：均衡器移动块失败：块 { ns: \"test.users\", min: { _id: 1 }, max: { _id: 100 } } 无法移动",
  "regex": "MongoServerError: balancer failed to move chunk: chunk \\{ ns: \".*\", min: \\{ .* \\}, max: \\{ .* \\} \\} could not be moved",
  "domain": "mongodb",
  "category": "runtime_error",
  "subcategory": null,
  "root_cause": "The balancer could not move a chunk because the target shard had insufficient storage or the chunk exceeded the maximum chunk size.",
  "root_cause_type": "generic",
  "root_cause_zh": "均衡器无法移动块，因为目标分片存储不足或块大小超过最大块大小。",
  "versions": [
    {
      "version": "mongodb-5.0",
      "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-7.0",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "",
      "why_fails": "Increasing chunkSize to a very large value can cause uneven data distribution and balancer inefficiency.",
      "fail_rate": 0.5,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "Disabling the balancer entirely stops automatic data redistribution, leading to uneven shard loads.",
      "fail_rate": 0.5,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "Manually splitting chunks without considering data distribution can create many small chunks that strain the balancer.",
      "fail_rate": 0.5,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "Check target shard disk usage with db.adminCommand({ listShards: 1 }) and add more shards or free up space on the target.",
      "success_rate": 0.8,
      "how": "Check target shard disk usage with db.adminCommand({ listShards: 1 }) and add more shards or free up space on the target.",
      "condition": "",
      "sources": []
    },
    {
      "action": "Reduce chunk size temporarily via mongos config: use sh.enableAutoSplit() and sh.setBalancerState(true) with smaller chunkSize (e.g., 64MB) to split large chunks before migration.",
      "success_rate": 0.75,
      "how": "Reduce chunk size temporarily via mongos config: use sh.enableAutoSplit() and sh.setBalancerState(true) with smaller chunkSize (e.g., 64MB) to split large chunks before migration.",
      "condition": "",
      "sources": []
    },
    {
      "action": "Manually move the chunk using sh.moveChunk() with a specific shard key range to force migration during low traffic.",
      "success_rate": 0.7,
      "how": "Manually move the chunk using sh.moveChunk() with a specific shard key range to force migration during low traffic.",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [
    "Check target shard disk usage with db.adminCommand({ listShards: 1 }) and add more shards or free up space on the target.",
    "Reduce chunk size temporarily via mongos config: use sh.enableAutoSplit() and sh.setBalancerState(true) with smaller chunkSize (e.g., 64MB) to split large chunks before migration.",
    "Manually move the chunk using sh.moveChunk() with a specific shard key range to force migration during low traffic."
  ],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": "https://www.mongodb.com/docs/manual/core/sharding-balancer-administration/",
  "official_doc_section": null,
  "error_code": null,
  "verification_tier": "ai_generated",
  "confidence": 0.85,
  "fix_success_rate": 0.78,
  "resolvable": "partial",
  "first_seen": "2024-02-10",
  "last_confirmed": "2024-06-01",
  "last_updated": "2024-06-01",
  "evidence_count": 1,
  "tags": [],
  "locale": "en",
  "aliases": []
}