90 + Interview Questions in Sharding Concepts in Mongodb Page 1 InterviewSolution

1.	_________ is an internal command that supports the sharding functionality.(a) getBalancerHost()(b) getShardMap(c) enableSharding()(d) all of the mentionedThe question was posed to me during a job interview.Query is from Sharded Cluster Data Management topic in division Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Right option is (B) getShardMap To EXPLAIN I would say: sh.getBalancerHost() RETURNS the name of a mongos that’s responsible for the BALANCER PROCESS.

Discussion

2.	You can only issue listShards against the ________ database.(a) local(b) admin(c) temp(d) none of the mentionedThe question was asked during an online interview.This intriguing question comes from Sharded Cluster Data Management topic in portion Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» The CORRECT CHOICE is (B) admin The best explanation: listShards is only available for mongos INSTANCES.

Discussion

3.	Which of the following command is used to determine split points?(a) splitVector(b) medianKey(c) movePrimary(d) none of the mentionedThe question was posed to me in semester exam.I need to ask this question from Sharded Cluster Data Management in portion Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Correct choice is (a) splitVector To ELABORATE: movePrimary reassigns the primary SHARD when removing a shard from a SHARDED cluster.

Discussion

4.	Which of the following command that validates index on shard key?(a) checkShardingIndex(b) checkSIndex(c) enableSharding(d) all of the mentionedThe question was posed to me in class test.This key question is from Sharded Cluster Data Management topic in division Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» The CORRECT choice is (a) checkShardingIndex Easy EXPLANATION: checkShardingIndex is an INTERNAL COMMAND that supports sharding FUNCTIONALITY.

Discussion

5.	Point out the wrong statement.(a) moveChunks provides the ability to combine chunks on a single shard(b) setShardVersion is used to set the config server version(c) shardCollection enables the sharding functionality for a collection, allowing the collection to be sharded(d) none of the mentionedI had been asked this question in exam.This intriguing question comes from Sharded Cluster Data Management in section Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Correct answer is (d) none of the mentioned Easiest explanation: For a sharded COLLECTION, mergeChunks combines contiguous chunk ranges on a SHARD into a SINGLE chunk.

Discussion

6.	_______ forces an update to the cluster metadata cached by a mongos.(a) config(b) flushconf(c) flushRouterConfig(d) all of the mentionedI had been asked this question by my school principal while I was bunking the class.The question is from Sharded Cluster Data Management topic in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» The correct option is (c) flushRouterConfig Easiest EXPLANATION: flushRouterConfig CLEARS the current CLUSTER information cached by a MONGOS instance and reloads all sharded cluster metadata from the config database.

Discussion

7.	_________ waits for a change in ping state from one of the mongos in the sharded cluster.(a) sh.waitForBalancer()(b) sh.startBalancer()(c) sh.waitForPingChange()(d) all of the mentionedThis question was addressed to me in semester exam.The above asked question is from Sharded Cluster Data Management topic in portion Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Correct option is (c) sh.waitForPingChange() EXPLANATION: sh.waitForBalancer() waits for the BALANCER state to CHANGE.

Discussion

8.	Point out the correct statement.(a) sh.deadForDLock() waits for a specified distributed sharded cluster lock(b) sh.waitForBalancerOff() waits until the balancer stops running(c) sh.statusserver() reports on the status of a sharded cluster, as db.printShardingStatus()(d) all of the mentionedThe question was asked by my school teacher while I was bunking the class.I need to ask this question from Sharded Cluster Data Management in section Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Correct OPTION is (a) sh.deadForDLock() waits for a specified distributed SHARDED cluster lock To elaborate: sh.stopBalancer() disables the BALANCER and waits for any in progress balancing rounds to complete.

Discussion

9.	_______ enables the balancer and waits for balancing to start.(a) sh.waitForBalancer()(b) sh.startBalancer()(c) sh.waitForDLock()(d) all of the mentionedThe question was asked in exam.My question is from Sharded Cluster Data Management topic in division Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Correct ANSWER is (B) sh.startBalancer() Easy explanation: sh.waitForDLock() waits for a SPECIFIED distributed sharded CLUSTER lock.

Discussion

10.	_______ activates the sharded collection balancer process if previously disabled using sh.disableBalancing().(a) sh.getBalancerHost()(b) sh.enableBalancing()(c) sh.enableSharding()(d) all of the mentionedI got this question by my school principal while I was bunking the class.Origin of the question is Sharded Cluster Data Management topic in portion Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» The CORRECT CHOICE is (a) sh.getBalancerHost() Explanation: sh.enableSharding() ENABLES sharding on a SPECIFIC database.

Discussion

11.	_________ disable balancing on a single collection in a sharded database.(a) sh.removeTagRange()(b) sh._checkMongos()(c) sh.disableBalancing()(d) none of the mentionedThis question was posed to me during an interview.My enquiry is from Sharded Cluster Data Management topic in section Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» RIGHT ANSWER is (c) sh.disableBalancing() To explain: sh.disableBalancing() does not AFFECT balancing of other collections in a sharded CLUSTER.

Discussion

12.	_________ removes an association between a range shard keys and a shard tag.(a) sh.removeTagRange()(b) sh._checkMongos()(c) sh.disableBalancing()(d) none of the mentionedI have been asked this question in an international level competition.My question is based upon Sharded Cluster Data Management topic in section Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Correct ANSWER is (a) sh.removeTagRange() The explanation: USE sh.removeShardTag() to ensure that unused or out of date RANGES are removed and HENCE CHUNKS are balanced as required.

Discussion

13.	_________ reports on the last chunk migration.(a) sh._checkMongos()(b) sh.addShard()(c) sh._lastMigration()(d) all of the mentionedThe question was asked in an interview for internship.I want to ask this question from Sharded Cluster Data Management topic in division Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» The correct CHOICE is (c) sh._lastMigration() Best EXPLANATION: The sh._lastMigration() method returns a document with details about the LAST migration performed on the database or COLLECTION.

Discussion

14.	Point out the wrong statement.(a) The best way to ensure a field has unique values is to generate universally unique identifiers (UUID,) such as MongoDB’s ‘ObjectId values(b) Most deployments will not need to shard the files collection(c) The files collection is typically small, and only contains metadata(d) None of the mentionedThis question was addressed to me during an internship interview.Origin of the question is Sharded Cluster Data Management topic in portion Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Correct option is (d) NONE of the mentioned The explanation is: None of the REQUIRED keys for GridFS LEND themselves to an EVEN distribution in a sharded SITUATION.

Discussion

15.	________ tests to see if the mongo shell is connected to a mongos instance.(a) sh._checkMongos()(b) sh.addShard()(c) sh._lastMigration()(d) all of the mentionedThis question was posed to me by my college director while I was bunking the class.Question is taken from Sharded Cluster Data Management in division Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» CORRECT OPTION is (a) sh._checkMongos() Explanation: The sh._checkMongos() method throws an error message if the mongo shell is not CONNECTED to a mongos INSTANCE.

Discussion

16.	_______ reports on the active balancer lock, if it exists.(a) sh._checkFullName()(b) sh._adminCommand()(c) sh.getBalancerLockDetails()(d) all of the mentionedThe question was asked by my school principal while I was bunking the class.Query is from Sharded Cluster Data Management in portion Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» CORRECT option is (c) sh.getBalancerLockDetails() The best EXPLANATION: sh._checkFullName() TESTS a namespace to DETERMINE if its well FORMED.

Discussion

17.	Point out the correct statement.(a) The unique constraint on indexes ensures that only one document can have a value for a field in a collection(b) MongoDB support creating new unique indexes in sharded collections(c) If you use a compound shard key, you cannot enforce uniqueness on the combination of component keys in the shard key(d) All of the mentionedI had been asked this question during an interview.I'd like to ask this question from Sharded Cluster Data Management topic in portion Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Right ANSWER is (a) The UNIQUE constraint on indexes ensures that only one document can have a value for a FIELD in a collection For explanation: For sharded collections these unique indexes cannot ENFORCE uniqueness because INSERT and indexing operations are local to each shard.

Discussion

18.	_______ runs a database command against the admin database of a mongos instance.(a) sh._checkFullName()(b) sh._adminCommand()(c) sh.getBalancerLockDetails()(d) all of the mentionedI had been asked this question during an internship interview.I'm obligated to ask this question of Sharded Cluster Data Management topic in section Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» CORRECT option is (b) sh._adminCommand() The best EXPLANATION: sh._adminCommand() runs a database command against the ADMIN database, like db.runCommand(), but can CONFIRM that it is ISSUED against a mongos.

Discussion

19.	Use ________ to ensure that the balancer migrates documents that exist within the specified range to a specific shard.(a) sh.addShardTag()(b) sh.addTag()(c) sh.aShardTag()(d) all of the mentionedThis question was addressed to me during an interview.This interesting question is from Troubleshooting Sharded Cluster topic in section Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» The CORRECT choice is (a) sh.addShardTag() EXPLANATION: Only ISSUE sh.addTagRange() when connected to a mongos instance.

Discussion

20.	Which of the following parameter represents minimum value of the shard key range to include in the tag?(a) min(b) max(c) maximum(d) minimumThe question was posed to me in an internship interview.I would like to ask this question from Troubleshooting Sharded Cluster in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Right option is (d) MINIMUM For explanation I would SAY: The minimum is an inclusive MATCH.

Discussion

21.	Each document in the tags holds the ________ of the sharded collection and a minimum shard key value.(a) tag(b) chunk(c) namespace(d) sizeI got this question in class test.My doubt is from Troubleshooting Sharded Cluster topic in division Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» CORRECT choice is (c) namespace Explanation: In most circumstances, you should LEAVE chunk splitting to the AUTOMATED processes WITHIN MongoDB.

Discussion

22.	To assign a tag to a range of shard keys use the _________ method when connected to a mongos instance.(a) sh.addTagRange()(b) sh.splitFind()(c) sh.Range()(d) all of the mentionedThe question was posed to me during an online interview.I would like to ask this question from Troubleshooting Sharded Cluster topic in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» CORRECT choice is (a) sh.addTagRange() To explain I WOULD say: You may delete tag assignment from a shard KEY range by removing the CORRESPONDING DOCUMENT from the tags collection of the config database.

Discussion

23.	Point out the wrong statement.(a) You cannot overlap defined ranges, or tag the same range more than once(b) The mongod provides a helper for removing a tag range(c) The output from sh.status() lists tags associated with a shard, if any, for each shard(d) None of the mentionedI had been asked this question during an interview for a job.The doubt is from Troubleshooting Sharded Cluster in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» RIGHT CHOICE is (b) The mongod provides a helper for REMOVING a TAG range To explain: The mongod does not provide a helper for removing a tag range.

Discussion

24.	________ associates a shard with a tag or identifier.(a) sh.collects()(b) sh.addShardTag(c) sh.results()(d) all of the mentionedThis question was addressed to me in unit test.The origin of the question is Troubleshooting Sharded Cluster topic in division Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Correct answer is (b) sh.addShardTag For explanation I would say: MongoDB uses these identifiers to direct CHUNKS that fall within a tagged RANGE to specific shards.

Discussion

25.	_________ is used to remove tags from a particular shard.(a) sh.removeTag()(b) sh.removeShard()(c) sh.removeShardTag()(d) all of the mentionedI got this question at a job interview.My query is from Troubleshooting Sharded Cluster in portion Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» CORRECT answer is (c) sh.removeShardTag() Best explanation: You MAY REMOVE TAGS from a particular shard using the sh.removeShardTag() METHOD when connected to a mongos instance.

Discussion

26.	Point out the correct statement.(a) In some instances, MongoDB cannot split the no-longer jumbo chunk, such as a chunk with a range of single shard key value(b) To ensure that mongos instances update their cluster information cache, run flushConfig in the admin database(c) In a sharded cluster, you cannot use tags to associate specific ranges of a shard key with a specific shard or subset of shards(d) All of the mentionedThe question was asked in an interview for internship.The above asked question is from Troubleshooting Sharded Cluster in division Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Correct CHOICE is (a) In some instances, MongoDB cannot split the no-longer JUMBO CHUNK, such as a chunk with a range of single shard key value Explanation: If you clear the jumbo flag for a chunk that still EXCEEDS the chunk SIZE and/or the document number limit, MongoDB will re-label the chunk as jumbo when MongoDB tries to move the chunk.

Discussion

27.	The preferred way to clear the _________ flag from a chunk is to attempt to split the chunk.(a) boolean(b) jumbo(c) change(d) all of the mentionedThis question was addressed to me in an interview.My question is taken from Troubleshooting Sharded Cluster in division Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Correct ANSWER is (b) jumbo To explain: If the CHUNK is DIVISIBLE, MongoDB removes the FLAG upon SUCCESSFUL split of the chunk.

Discussion

28.	The mergeChunks command requires at least _______ empty input chunk.(a) one(b) two(c) three(d) all of the mentionedThis question was addressed to me in homework.Enquiry is from Sharded Cluster Maintenance topic in portion Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Correct OPTION is (a) one The best I can explain: MergeChunks merge two contiguous chunks on the same SHARD, where at least one of the contains no DATA.

Discussion

29.	sh.splitFind () Splits the chunk that contains the shard key value specified by the query at the chunk’s ______ point.(a) smean(b) stdev(c) median(d) all of the mentionedThis question was posed to me during an internship interview.The origin of the question is Sharded Cluster Maintenance in section Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» CORRECT option is (C) median To explain I would say: It may be BENEFICIAL to pre-split MANUALLY an empty collection using methods such as sh.splitFind().

Discussion

30.	_________ splits a chunk at the shard key value specified by the query.(a) sh.Find()(b) sh.splitFind()(c) sh.split()(d) sh.splitAtThis question was addressed to me in quiz.This interesting question is from Sharded Cluster Maintenance topic in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Right answer is (d) sh.splitAt The BEST explanation: In most circumstances, you should leave chunk splitting to the AUTOMATED PROCESSES within MongoDB.

Discussion

31.	__________ splits the chunk that contains the shard key value specified by the query at the chunk’s median point.(a) sh.Find()(b) sh.splitFind()(c) sh.split()(d) all of the mentionedThe question was posed to me in final exam.This interesting question is from Sharded Cluster Maintenance in division Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» The correct choice is (b) sh.splitFind() EXPLANATION: sh.splitFind() CREATES two roughly equal chunks.

Discussion

32.	Point out the wrong statement.(a) If a collection already has data, MongoDB automatically splits the collection’s data when you enable sharding for the collection(b) Subsequent attempts to manually create splits can lead to unpredictable chunk ranges and sizes as well as inefficient or ineffective balancing behavior(c) MongoDB creates splits only after an insert operation(d) None of the mentionedThe question was asked in an interview for job.I'm obligated to ask this question of Sharded Cluster Maintenance in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» The correct choice is (d) None of the mentioned To explain I WOULD say: The DEFAULT behavior SUPPRESSES the detailed chunk INFORMATION if the total number of chunks is greater than or equal to 20.

Discussion

33.	Use ________ to determine the current chunk ranges across the cluster.(a) sh.collects()(b) sh.status()(c) sh.results()(d) all of the mentionedThis question was posed to me in unit test.Enquiry is from Sharded Cluster Maintenance in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» The correct OPTION is (b) sh.status() Explanation: To access the config database, connect to a mongos INSTANCE in a SHARDED CLUSTER, and use the FOLLOWING helper: use config

Discussion

34.	MongoDB provides the _________ command to combine contiguous chunk ranges into a single chunk.(a) helpchunks(b) moveChunks(c) mergeChunks(d) all of the mentionedThe question was asked during an internship interview.Question is from Sharded Cluster Maintenance in section Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» The CORRECT answer is (c) mergeChunks The explanation is: For a sharded collection, mergeChunks COMBINES contiguous chunk RANGES on a shard into a single chunk. Issue the mergeChunks command from a mongos instance.

Discussion

35.	Point out the correct statement.(a) Pre-splitting the chunk ranges in an empty sharded collection allows clients to insert data into an already partitioned collection(b) MongoDB cannot create enough chunks or distribute data fast enough to support required throughput(c) Chunk migration does not require copying all the data in the chunk from one shard to another(d) All of the mentionedI had been asked this question during an internship interview.This question is from Sharded Cluster Maintenance in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» The correct answer is (a) Pre-splitting the chunk ranges in an empty sharded collection ALLOWS clients to insert data into an ALREADY PARTITIONED collection Explanation: In most situations a sharded cluster will CREATE and DISTRIBUTE chunks automatically without user intervention.

Discussion

36.	Split empty chunks in your collection by manually performing the ______ command on chunks.(a) distrbute(b) split(c) change(d) all of the mentionedI had been asked this question in a national level competition.Asked question is from Sharded Cluster Maintenance topic in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Right CHOICE is (b) split The best explanation: The config database is internal: applications and ADMINISTRATORS should not modify or depend upon its content in the COURSE of NORMAL OPERATION.

Discussion

37.	If the collection is empty then MongoDB will create the index as part of the ________(a) shardCollectionkey()(b) shardCollection()(c) keyCollection()(d) all of the mentionedI got this question during an online exam.The origin of the question is Cluster Deployment in portion Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Correct answer is (b) shardCollection() EASY EXPLANATION: MongoDB provides no method to deactivate sharding for a COLLECTION after calling shardCollection.

Discussion

38.	Changing the _______ option will change the port that mongod listens for incoming connections on.(a) –shardsrvkey(b) –shardsrv(c) –shard(d) All of the mentionedThis question was addressed to me during a job interview.This intriguing question comes from Cluster Deployment topic in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» CORRECT ANSWER is (b) –shardsrv To elaborate: The single-shard CLUSTER is now a non-sharded replica set that will accept read and write OPERATIONS on the data set.

Discussion

39.	The _______ collection keeps track of the active components in the sharded cluster.(a) deploys(b) lockpings(c) locks(d) all of the mentionedThe question was posed to me in an online interview.The query is from Cluster Deployment in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» CORRECT option is (B) lockpings Best explanation: The locks COLLECTION STORES a distributed lock.

Discussion

40.	________ is a string that holds the address of the client, a mongos instance that initiates this change.(a) config.changelog.serverAddr(b) config.changelog.clientAddr(c) config.changelog.time(d) all of the mentionedThis question was posed to me in an online quiz.Query is from Cluster Deployment topic in section Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» The CORRECT OPTION is (b) config.changelog.clientAddr Easy explanation: config.changelog.time is ISODate timestamp that REFLECTS when the CHANGE OCCURRED.

Discussion

41.	Point out the wrong statement.(a) Database servers store the metadata for a sharded cluster(b) Always back up the config database before doing any maintenance on the config server(c) The mongos instances cache metadata and use it to route read and write operations to shards(d) None of the mentionedThe question was posed to me in examination.My question is based upon Cluster Deployment in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» RIGHT choice is (a) DATABASE servers store the metadata for a sharded cluster For explanation: The metadata REFLECTS STATE and organization of the sharded data sets and SYSTEM.

Discussion

42.	Point out the correct statement.(a) The local database supports sharded cluster operation(b) The config database is a dependable API, and users should not write data to the config database in the course of normal operation or maintenance(c) Modification of the config database on a functioning system may lead to instability or inconsistent data sets(d) All of the mentionedThe question was posed to me during an interview.This interesting question is from Cluster Deployment in division Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Right option is (C) Modification of the config DATABASE on a functioning system may lead to instability or INCONSISTENT data sets The explanation is: If you MUST modify the config database, use MONGODUMP to create a full backup of the config database.

Discussion

43.	You can return a list of the collections, with the following helper ______________(a) show collects(b) show collection(c) show collections(d) all of the mentionedThe question was posed to me in an international level competition.I'm obligated to ask this question of Cluster Deployment topic in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Right CHOICE is (C) SHOW collections Easiest explanation: To access the CONFIG database, connect to a mongos instance in a sharded cluster, and use the FOLLOWING helper: use config.

Discussion

44.	The _________ collection stores a document for each sharded collection in the cluster.(a) help(b) shards(c) collections(d) all of the mentionedThis question was posed to me during an interview.The above asked question is from Cluster Deployment in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» The correct answer is (c) collections Easy EXPLANATION: SHARD KEYS are immutable and cannot be changed after insertion.

Discussion

45.	The ________ collection stores a document for each change to the metadata of a sharded collection.(a) version(b) changelog(c) settings(d) all of the mentionedThe question was posed to me by my college professor while I was bunking the class.My doubt stems from Cluster Deployment in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Right answer is (b) changelog For explanation: The CONFIG database is internal: applications and administrators should not modify or DEPEND UPON its content in the course of normal OPERATION.

Discussion

46.	You can set the _________ option on the balancer configuration to set different write concern semantics.(a) writeConcern(b) updateConcern(c) readConcern(d) all of the mentionedThis question was addressed to me by my college director while I was bunking the class.This interesting question is from Sharding Mechanics topic in portion Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» The correct choice is (a) writeConcern The best EXPLANATION: By DEFAULT, each document operation during chunk migration propagates to at least one SECONDARY before the BALANCER PROCEEDS with the next docume

Discussion

47.	The default value _________ becomes true for all chunk migrations.(a) secThrottle(b) secondaryThrottle(c) primaryThrottle(d) all of the mentionedI had been asked this question in an international level competition.My question is based upon Sharding Mechanics in division Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Correct answer is (b) secondaryThrottle The best explanation: The NEW writeConcern field in the balancer configuration document allows you to specify a write concern SEMANTICS the _secondaryThrottle OPTION.

Discussion

48.	________ can alter the behavior so that the delete phase of the current migration blocks the start of the next chunk migration.(a) _waitForUpdate(b) _waitForDelete(c) _waitForInsert(d) All of the mentionedThe question was posed to me in unit test.My doubt is from Sharding Mechanics in division Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» RIGHT answer is (b) _waitForDelete To explain I would SAY: The _waitForDelete is generally for INTERNAL TESTING PURPOSES.

Discussion

49.	The source shard is responsible for incoming ______ operations for the chunk.(a) read(b) write(c) read-write(d) all of the mentionedThis question was posed to me in class test.The query is from Sharding Mechanics topic in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» Right option is (b) write Easy EXPLANATION: During the migration PROCESS, OPERATIONS to the CHUNK route to the SOURCE shard.

Discussion

50.	The balancer process sends the _______ command to the source shard.(a) moveChunkShard(b) migChunk(c) moveChunk(d) all of the mentionedThe question was posed to me in quiz.The question is from Sharding Mechanics topic in portion Sharding Concepts, Mechanics and Sharded Cluster of MongoDB
Answer» CORRECT OPTION is (C) moveChunk For explanation: The source starts the MOVE with an INTERNAL moveChunk command.

Discussion

Explore topic-wise InterviewSolutions in .

Each document in the tags holds the ________ of the sharded collection and a minimum shard key value.(a) tag(b) chunk(c) namespace(d) sizeI got this question in class test.My doubt is from Troubleshooting Sharded Cluster topic in division Sharding Concepts, Mechanics and Sharded Cluster of MongoDB

The mergeChunks command requires at least _______ empty input chunk.(a) one(b) two(c) three(d) all of the mentionedThis question was addressed to me in homework.Enquiry is from Sharded Cluster Maintenance topic in portion Sharding Concepts, Mechanics and Sharded Cluster of MongoDB

Use ________ to determine the current chunk ranges across the cluster.(a) sh.collects()(b) sh.status()(c) sh.results()(d) all of the mentionedThis question was posed to me in unit test.Enquiry is from Sharded Cluster Maintenance in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB

The _______ collection keeps track of the active components in the sharded cluster.(a) deploys(b) lockpings(c) locks(d) all of the mentionedThe question was posed to me in an online interview.The query is from Cluster Deployment in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB

The source shard is responsible for incoming ______ operations for the chunk.(a) read(b) write(c) read-write(d) all of the mentionedThis question was posed to me in class test.The query is from Sharding Mechanics topic in chapter Sharding Concepts, Mechanics and Sharded Cluster of MongoDB

The balancer process sends the _______ command to the source shard.(a) moveChunkShard(b) migChunk(c) moveChunk(d) all of the mentionedThe question was posed to me in quiz.The question is from Sharding Mechanics topic in portion Sharding Concepts, Mechanics and Sharded Cluster of MongoDB