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The balancer is running even though it's disabled: mongos> sh.getBalancerState() false mongos> sh.isBalancerRunning() true In config.locks there is a balancer entry: mongos> db.locks.find({_id:"balancer"}) { "_id" : "balancer", "state" : 2, "ts" : ObjectId("59b93d04d035a79b193cea5b"), "who" : "ConfigServer:Balancer", "process" : "ConfigServer", "when" : ISODate("2017-09-13T14:13:37.034Z"), "why" : "CSRS Balancer" } We restarted all routers (mongos) and configservers but the balancer is still running. Btw. the dbs is not yet in use and therefore nearly empty since it's not yet in production. mongos> show dbs admin 0.000GB config 0.007GB mongos> sh.status() --- Sharding Status --- sharding version: { "_id" : 1, "minCompatibleVersion" : 5, "currentVersion" : 6, "clusterId" : ObjectId("598ab847e97e92ba40fa56ee") } shards: { "_id" : "offerHistory01", "host" : "offerHistory01/mongo-016.db00.pro06.eu.idealo.com:27017,mongo-105.db00.pro05.eu.idealo.com:27017", "state" : 1 } { "_id" : "offerHistory02", "host" : "offerHistory02/mongo-119.db00.pro06.eu.idealo.com:27017,mongo-120.db00.pro06.eu.idealo.com:27017", "state" : 1 } { "_id" : "offerHistory03", "host" : "offerHistory03/mongo-121.db00.pro06.eu.idealo.com:27017,mongo-122.db00.pro06.eu.idealo.com:27017", "state" : 1 } { "_id" : "offerHistory04", "host" : "offerHistory04/mongo-047.db00.pro06.eu.idealo.com:27017,mongo-123.db00.pro06.eu.idealo.com:27017", "state" : 1 } active mongoses: "3.4.6" : 5 balancer: Currently enabled: no Currently running: yes Balancer lock taken at Wed Sep 13 2017 16:13:37 GMT+0200 (CEST) by ConfigServer:Balancer Failed balancer rounds in last 5 attempts: 5 Last reported error: Cannot accept sharding commands if not started with --shardsvr Time of Reported error: Fri Aug 25 2017 08:46:00 GMT+0200 (CEST) Migration Results for the last 24 hours: 3 : Success databases: mongos>

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kaloian.manassiev commented on Thu, 14 Sep 2017 14:19:58 +0000: Thanks for confirming, kay.agahd@idealo.de! Just for posterity, this is the documentation link, which explains the 3.4 behaviour change: https://docs.mongodb.com/manual/tutorial/manage-sharded-cluster-balancer/#check-if-balancer-is-running kay.agahd@idealo.de commented on Thu, 14 Sep 2017 14:15:14 +0000: Hi kaloian.manassiev, that's it, you're right! We were using a mongo shell v3.2. Using mongo shell v3.4 correctly shows that the balancer is stopped: MongoDB shell version v3.4.6 connecting to: mongodb://localhost:27017/admin MongoDB server version: 3.4.6 mongos> sh.getBalancerState() false mongos> sh.isBalancerRunning() false mongos> You may close this ticket as resolved. Thanks! kaloian.manassiev commented on Thu, 14 Sep 2017 14:04:59 +0000: Hi kay.agahd@idealo.de, Can you please confirm whether you are running version 3.4 of the mongo shell to run these commands? In MongoDB 3.4 we moved the balancer to run on the CSRS config server's primary and as a result it now permanently holds the balancer lock in order to prevent any accidentally left 3.2 or prior mongos instances for doing balancing. Because of this, all functions from shells before 3.4, which rely on the status of the balancer lock, no longer work. Instead, we introduced a new command. Best regards, -Kal. kay.agahd@idealo.de commented on Thu, 14 Sep 2017 08:10:06 +0000: Hello mark.agarunov, I tried to upload the log files without success scp -P 722 file.log.tgz SERVER-31075@www.mongodb.com: Could you provide us a non-public upload location please? We generally keep our log files for only 7 days so probably the log file containing the cause has been rotated already. However, I kept the log file of the router which was exclusively used during our pre-service testing. It may contain what you are looking for. Its size is 991 MB uncompressed, 66 MB compressed. mark.agarunov commented on Wed, 13 Sep 2017 20:20:58 +0000: Hello kay.agahd@idealo.de, Thank you for the report. It seems from the output that there may be a lock that has not been relinquished from a previous run of the balancer. To get a better idea of what may be causing this, could you please provide the logs from all affected mongos and mongod nodes? Thanks, Mark kay.agahd@idealo.de commented on Wed, 13 Sep 2017 14:49:06 +0000: Also quite weird: mongos> db.settings.find() { "_id" : "balancer", "stopped" : true, "mode" : "full" } { "_id" : "chunksize", "value" : 1024 } mongos> sh.isBalancerRunning() true

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