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I have configured a sharded cluster on aws on a replicaSet composed on two server, a config server and a front server and mongo 3.4. I followed mainly this tutorial :

The configuration seems correct. however, when I tried to insert 1.000.000 docuements on the clients collection, the data was not chunked.

Could you help please.

mongos> db.printShardingStatus({verbose:true})
--- Sharding Status --- 
  sharding version: {
    "_id" : 1,
    "minCompatibleVersion" : 5,
    "currentVersion" : 6,
    "clusterId" : ObjectId("59fb2f9173d9611f98c95eb3")
  }
  shards:
        {  "_id" : "rs1",  "host" : "rs1/172.31.12.34:27018,172.31.13.80:27018",  "state" : 1 }
  active mongoses:
        {  "_id" : "ip-172-31-25-254:27017",  "ping" : ISODate("2017-11-02T23:04:26.780Z"),  "up" : NumberLong(14602),  "waiting" : true,  "mongoVersion" : "3.4.10" }
  autosplit:
        Currently enabled: yes
  balancer:
        Currently enabled:  yes
        Currently running:  no
NaN
        Failed balancer rounds in last 5 attempts:  5
        Last reported error:  could not find host matching read preference { mode: "primary" } for set rs2
        Time of Reported error:  Thu Nov 02 2017 18:56:13 GMT+0000 (UTC)
        Migration Results for the last 24 hours: 
                No recent migrations
  databases:
        {  "_id" : "tests",  "primary" : "rs1",  "partitioned" : true }
                tests.clients
                        shard key: { "num" : 1 }
                        unique: false
                        balancing: true
                        chunks:
                                rs1 1
                        { "num" : { "$minKey" : 1 } } -->> { "num" : { "$maxKey" : 1 } } on : rs1 Timestamp(1, 0) 



mongos> db.clients.stats()
{
  "sharded" : true,
  "capped" : false,
  "ns" : "tests.clients",
  "count" : 1000000,
  "size" : 35000000,
  "storageSize" : 12296192,
  "totalIndexSize" : 9867264,
  "indexSizes" : {
    "_id_" : 9867264
  },
  "avgObjSize" : 35,
  "nindexes" : 1,
  "nchunks" : 1,
  "shards" : {
    "rs1" : {
      "ns" : "tests.clients",
      "size" : 35000000,
      "count" : 1000000,
      "avgObjSize" : 35,
      "storageSize" : 12296192,
      "capped" : false,
      "wiredTiger" : {
        "metadata" : {
          "formatVersion" : 1
        },
        "creationString" : "access_pattern_hint=none,allocation_size=4KB,app_metadata=(formatVersion=1),block_allocation=best,block_compressor=snappy,cache_resident=false,checksum=on,colgroups=,collator=,columns=,dictionary=0,encryption=(keyid=,name=),exclusive=false,extractor=,format=btree,huffman_key=,huffman_value=,ignore_in_memory_cache_size=false,immutable=false,internal_item_max=0,internal_key_max=0,internal_key_truncate=true,internal_page_max=4KB,key_format=q,key_gap=10,leaf_item_max=0,leaf_key_max=0,leaf_page_max=32KB,leaf_value_max=64MB,log=(enabled=true),lsm=(auto_throttle=true,bloom=true,bloom_bit_count=16,bloom_config=,bloom_hash_count=8,bloom_oldest=false,chunk_count_limit=0,chunk_max=5GB,chunk_size=10MB,merge_max=15,merge_min=0),memory_page_max=10m,os_cache_dirty_max=0,os_cache_max=0,prefix_compression=false,prefix_compression_min=4,source=,split_deepen_min_child=0,split_deepen_per_child=0,split_pct=90,type=file,value_format=u",
        "type" : "file",
        "uri" : "statistics:table:collection-11-1418402185877323060",
        "LSM" : {
          "bloom filter false positives" : 0,
          "bloom filter hits" : 0,
          "bloom filter misses" : 0,
          "bloom filter pages evicted from cache" : 0,
          "bloom filter pages read into cache" : 0,
          "bloom filters in the LSM tree" : 0,
          "chunks in the LSM tree" : 0,
          "highest merge generation in the LSM tree" : 0,
          "queries that could have benefited from a Bloom filter that did not exist" : 0,
          "sleep for LSM checkpoint throttle" : 0,
          "sleep for LSM merge throttle" : 0,
          "total size of bloom filters" : 0
        },
        "block-manager" : {
          "allocations requiring file extension" : 1454,
          "blocks allocated" : 1622,
          "blocks freed" : 109,
          "checkpoint size" : 12238848,
          "file allocation unit size" : 4096,
          "file bytes available for reuse" : 40960,
          "file magic number" : 120897,
          "file major version number" : 1,
          "file size in bytes" : 12296192,
          "minor version number" : 0
        },
        "btree" : {
          "btree checkpoint generation" : 379,
          "column-store fixed-size leaf pages" : 0,
          "column-store internal pages" : 0,
          "column-store variable-size RLE encoded values" : 0,
          "column-store variable-size deleted values" : 0,
          "column-store variable-size leaf pages" : 0,
          "fixed-record size" : 0,
          "maximum internal page key size" : 368,
          "maximum internal page size" : 4096,
          "maximum leaf page key size" : 2867,
          "maximum leaf page size" : 32768,
          "maximum leaf page value size" : 67108864,
          "maximum tree depth" : 3,
          "number of key/value pairs" : 0,
          "overflow pages" : 0,
          "pages rewritten by compaction" : 0,
          "row-store internal pages" : 0,
          "row-store leaf pages" : 0
        },
        "cache" : {
          "bytes currently in the cache" : 10945398,
          "bytes read into cache" : 0,
          "bytes written from cache" : 43275208,
          "checkpoint blocked page eviction" : 0,
          "data source pages selected for eviction unable to be evicted" : 0,
          "hazard pointer blocked page eviction" : 0,
          "in-memory page passed criteria to be split" : 18,
          "in-memory page splits" : 9,
          "internal pages evicted" : 0,
          "internal pages split during eviction" : 0,
          "leaf pages split during eviction" : 29,
          "modified pages evicted" : 29,
          "overflow pages read into cache" : 0,
          "overflow values cached in memory" : 0,
          "page split during eviction deepened the tree" : 0,
          "page written requiring lookaside records" : 0,
          "pages read into cache" : 0,
          "pages read into cache requiring lookaside entries" : 0,
          "pages requested from the cache" : 1000028,
          "pages written from cache" : 1577,
          "pages written requiring in-memory restoration" : 2,
          "tracked dirty bytes in the cache" : 0,
          "unmodified pages evicted" : 1195
        },
        "cache_walk" : {
          "Average difference between current eviction generation when the page was last considered" : 0,
          "Average on-disk page image size seen" : 0,
          "Clean pages currently in cache" : 0,
          "Current eviction generation" : 0,
          "Dirty pages currently in cache" : 0,
          "Entries in the root page" : 0,
          "Internal pages currently in cache" : 0,
          "Leaf pages currently in cache" : 0,
          "Maximum difference between current eviction generation when the page was last considered" : 0,
          "Maximum page size seen" : 0,
          "Minimum on-disk page image size seen" : 0,
          "On-disk page image sizes smaller than a single allocation unit" : 0,
          "Pages created in memory and never written" : 0,
          "Pages currently queued for eviction" : 0,
          "Pages that could not be queued for eviction" : 0,
          "Refs skipped during cache traversal" : 0,
          "Size of the root page" : 0,
          "Total number of pages currently in cache" : 0
        },
        "compression" : {
          "compressed pages read" : 0,
          "compressed pages written" : 1526,
          "page written failed to compress" : 0,
          "page written was too small to compress" : 51,
          "raw compression call failed, additional data available" : 0,
          "raw compression call failed, no additional data available" : 0,
          "raw compression call succeeded" : 0
        },
        "cursor" : {
          "bulk-loaded cursor-insert calls" : 0,
          "create calls" : 5,
          "cursor-insert key and value bytes inserted" : 38917635,
          "cursor-remove key bytes removed" : 0,
          "cursor-update value bytes updated" : 0,
          "insert calls" : 1000000,
          "next calls" : 1,
          "prev calls" : 1,
          "remove calls" : 0,
          "reset calls" : 1000002,
          "restarted searches" : 0,
          "search calls" : 0,
          "search near calls" : 0,
          "truncate calls" : 0,
          "update calls" : 0
        },
        "reconciliation" : {
          "dictionary matches" : 0,
          "fast-path pages deleted" : 0,
          "internal page key bytes discarded using suffix compression" : 4198,
          "internal page multi-block writes" : 18,
          "internal-page overflow keys" : 0,
          "leaf page key bytes discarded using prefix compression" : 0,
          "leaf page multi-block writes" : 52,
          "leaf-page overflow keys" : 0,
          "maximum blocks required for a page" : 54,
          "overflow values written" : 0,
          "page checksum matches" : 644,
          "page reconciliation calls" : 93,
          "page reconciliation calls for eviction" : 29,
          "pages deleted" : 0
        },
        "session" : {
          "object compaction" : 0,
          "open cursor count" : 1
        },
        "transaction" : {
          "update conflicts" : 0
        }
      },
0

As your sh.status() says:

shards:
    {  "_id" : "rs1",  "host" : "rs1/172.31.12.34:27018,172.31.13.80:27018",  "state" : 1 }

You have only ONE shard active in your cluster. There is no place where balancer could balance.

Error message says:

could not find host matching read preference { mode: "primary" } for set rs2

So, check your configuration. RS2 that it is working (it have primary) and it is added to cluster and listed in the sh.status().

  • I added the second shard as you requested. however, nothing changer. I remodved all the existing documents and added 1.000.000 new document. – Adel Essafi Nov 3 '17 at 10:37
  • this is my request : for (i=0;i<1000000;i++) db.clients.insert({num:i}) – Adel Essafi Nov 3 '17 at 11:48
  • You don't have enough data to have split! (64MB of data) You have only ONE chunk, chunks: rs1 1. You can use for (var x=1;x<100000;x=x+1000) {printjson(sh.splitAt("tests.clients",{"num" : x}));} to generate more chunks. – JJussi Nov 4 '17 at 9:35
  • should I be admin to create chunks?? – Adel Essafi Nov 5 '17 at 18:22
  • Yes.. You need to be admin or root. dbOwner should be enough too. – JJussi Nov 5 '17 at 18:24
0

I added the second shard as you requested. however, nothing changer. I remodved all the existing documents and added 1.000.000 new document.

mongos> sh.status()
--- Sharding Status --- 
  sharding version: {
    "_id" : 1,
    "minCompatibleVersion" : 5,
    "currentVersion" : 6,
    "clusterId" : ObjectId("59fb2f9173d9611f98c95eb3")
  }
  shards:
        {  "_id" : "rs1",  "host" : "rs1/172.31.12.34:27018,172.31.13.80:27018",  "state" : 1 }
        {  "_id" : "rs2",  "host" : "rs2/ip-172-31-0-181:27018",  "state" : 1 }
  active mongoses:
        "3.4.10" : 1
  autosplit:
        Currently enabled: yes
  balancer:
        Currently enabled:  yes
        Currently running:  no
NaN
        Failed balancer rounds in last 5 attempts:  5
        Last reported error:  could not find host matching read preference { mode: "primary" } for set rs2
        Time of Reported error:  Thu Nov 02 2017 18:56:13 GMT+0000 (UTC)
        Migration Results for the last 24 hours: 
                No recent migrations
  databases:
        {  "_id" : "tests",  "primary" : "rs1",  "partitioned" : true }
                tests.clients
                        shard key: { "num" : 1 }
                        unique: false
                        balancing: true
                        chunks:
                                rs1 1
                        { "num" : { "$minKey" : 1 } } -->> { "num" : { "$maxKey" : 1 } } on : rs1 Timestamp(1, 0) 
                tests.vquest_metadata
                        shard key: { "_id" : 1 }
                        unique: false
                        balancing: true
                        chunks:
                                rs1 1
                        { "_id" : { "$minKey" : 1 } } -->> { "_id" : { "$maxKey" : 1 } } on : rs1 Timestamp(1, 0) 

mongos> 

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