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This article will explain in detail how to modify oplogSize in MongoDB. The content of the article is of high quality, so the editor shares it for you as a reference. I hope you will have a certain understanding of the relevant knowledge after reading this article.

1. Close the node and start it with a single instance. 1.1.The process of shutting down the node SECONDARY > db.shutdownServer () 1.2Log out the startup parameters related to Replica set.

And modify the port number (assuming it was 27001, now it is 37001)

1.3 restart / apps/mongodb/bin/mongod-f / data/johnny/cfg/shard1.cnf2, backup node oplog log

Complete all oplog records of the current node

Mongodump-port 37001-db local-collection 'oplog.rs'

Back up the most recent oplog record in oplog.rs

> use local > db.optmp.drop ()-clear the temporary table Store the most recent record in oplog > db.optmp.save (db.oplog.rs.find ({}, {ts: 1, h: 1}). Sort ({$natural:-1}). Limit (1). Next ()-- store the most recent record in a temporary collection > db.optmp.find ()-- verify that the record has been stored in {"_ id": ObjectId ("5a0d437ed4738d194fa0b94f"), "ts": Timestamp (1510389543). 1), "h": NumberLong ("- 2633465233485407995")} 3, modify oplogSize

Delete the original oplog.rs collection

> use local > db.oplog.rs.drop ()

Create a new oplog.rs collection

> db.runCommand ({create: "oplog.rs", capped: true Size: (2 * 1024 * 1024 * 1024)} {"ok": 1}-if successful, ok4 will be returned and the last record backed up before will be restored > db.oplog.rs.save (db.optmp.findOne ()) > db.oplog.rs.find ()-query to verify whether 5, Rejoin replica set 5.1 close the current single instance process > db.shutdownServer () 5.2 restore profile information

(note the modification of the oplogSizeMB parameter value)

Start the instance process / apps/mongodb/bin/mongod-f / data/johnny/cfg/shard1.cnf6 and check the node status

Log in to mongo shell to check whether the node has successfully joined the replica set schema

> rs.status () check whether oplogSize is valid (red font) SECONDARY > rs.printReplicationInfo () configured oplog size: 2048MBlog length start to end: 0secs (0hrs) oplog first event time: Sat Nov 11 2017 16:39:03 GMT+0800 (CST) oplog last event time: Sat Nov 11 2017 16:39:03 GMT+0800 (CST) now: Thu Nov 16 2017 17:00:32 GMT+0800 (CST) 7, modify the oplogSize parameters of other members of the replica set in turn according to the above steps

Note: when modifying the Primary node, remember to use the following command to downgrade before modifying

Primary > rs.stepDown ()-can produce election method 2 more effectively:

Dynamic modification methods supported after version 3.6

1. Modify the parameter size before: replication: oplogSizeMB: 1024 replSetName: shardrs1

Check the oplog.rs collection size after logging in to mongo shell

> use localswitched to db local > db.oplog.rs.stats (). MaxSizeNumberLong (1073741824)-unit bytes, that is, 2014MB2. Modify > use localswitched to db local > db.adminCommand ({replSetResizeOplog:1, size: 2048}) through the administrative command -2048 units also MB {"ok": 1, "operationTime": Timestamp (1537776585, 1), "$clusterTime": {"clusterTime": Timestamp (1537776585, 1), "signature": {"hash": BinData (0, "AAAAAAAAAAAAAAAAAAAAAAAAAAA="), "keyId": NumberLong (0)}} 3. Verify success > db.oplog.rs.stats () .maxSizeNumberLong ("2147483648")

So far, our oplog size has been dynamically modified, is it very simple, is it very easy?

Think about:

Ask the 1:replSetResizeOplog command whether the replication.oplogSizeMB parameter value has been changed at the same time.

A: I checked the startup configuration file at this time and found that the oplogSizeMB is still 1024

Q2: will the parameter values in the configuration file be changed to modified values after reboot?

A: after restarting the database instance, I found that there was no such thing as the initial value.

Q3: will the newly modified values expire after reboot?

A: I found out again that I didn't. I still used the latest value.

Shardrs1:PRIMARY > db.oplog.rs.stats (). MaxSizeNumberLong ("2147483648") on how to modify oplogSize in MongoDB is shared here, I hope the above content can be helpful to you, can learn more knowledge. If you think the article is good, you can share it for more people to see.

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