See the master-slave operation log in the MongoDB replication set Oplog

The replica set schema of MongoDB is a log to store write operations, and this log is called Oplog. Oplog.rs is a fixed-length Capped Collection that exists in the local database and is used to log replicasets operations. By default, for 64-bit mongodb,oplog is relatively large, can reach 5% of the disk space, the size of Oplog can be mongod parameter "-oplogsize" to change the Oplog log size.

Oplog Sample content:

> Use Local

> Show Collections

> Db.oplog.rs.find ()

The new version has a problem, can no longer be as direct as the old version of the operation, you must first add an administrator user, then switch to the administrator identity, and then to operate, see the log.

Rs1:primary> Show Dbsshow DBS

2016-07-22t17:44:25.491+0800 E QUERY [thread1] error:listdatabases failed:{

"OK": 0,

"ErrMsg": "Not authorized in Admin to execute command {listdatabases:1.0}",

"Code": 13

} :

[Email protected]/mongo/shell/utils.js:25:13

[Email protected]/mongo/shell/mongo.js:62:1

[Email protected]/mongo/shell/utils.js:761:19

[Email protected]/mongo/shell/utils.js:651:15

@ (SHELLHELP2): 1:1

rs1:primary> Use Localuse Local

Switched to DB Local

Rs1:primary> Show Collectionsshow Collections

2016-07-22t17:44:40.317+0800 E QUERY [Thread1] Error:listcollections failed: {

"OK": 0,

"ErrMsg": "Not authorized on local to execute command {listcollections:1.0, filter: {}}",

"Code": 13

} :

[Email protected]/mongo/shell/utils.js:25:13

[Email protected]/mongo/shell/db.js:773:1

[Email protected]/mongo/shell/db.js:785:19

[Email protected]/mongo/shell/db.js:796:16

[Email Protected]/mongo/shell/utils.js:754:9

[Email protected]/mongo/shell/utils.js:651:15

@ (SHELLHELP2): 1:1

rs1:primary> Use Adminuse Admin

Switched to DB admin

Rs1:primary> Db.createuser (Db.createuser (

... {      {

... User: "BBB", User: "BBB",

... pwd: "BBB", pwd: "BBB",

... roles: [{role: "root", DB: "admin"}] roles: [{role: "root", DB: "admin"}]

...       } }

...     ) )

Successfully added User: {

"User": "BBB",

"Roles": [

{

"Role": "Root",

"DB": "admin"

}

]

}

Rs1:primary> Show Dbsshow DBS

2016-07-22t17:45:54.756+0800 E QUERY [thread1] error:listdatabases failed:{

"OK": 0,

"ErrMsg": "Not authorized in Admin to execute command {listdatabases:1.0}",

"Code": 13

} :

[Email protected]/mongo/shell/utils.js:25:13

[Email protected]/mongo/shell/mongo.js:62:1

[Email protected]/mongo/shell/utils.js:761:19

[Email protected]/mongo/shell/utils.js:651:15

@ (SHELLHELP2): 1:1

rs1:primary> Db.auth (' BBB ', ' BBB ') Db.auth (' BBB ', ' BBB ') // we have certified here to operate.

1

rs1:primary> Use Localuse Local

Switched to DB Local

Rs1:primary> Show Collectionsshow Collections

Me

Oplog.rs

Replset.election

Startup_log

System.replset

Rs1:primary> Db.oplog.rs.find () Db.oplog.rs.find ()

{"TS": Timestamp (1469180416, 1), "H": Numberlong ("6313428569778261950"), "V": 2, "OP": "N", "ns": "", "O": {"MSG" : "Initiating Set"}}

{"TS": Timestamp (1469180428, 2), "T": Numberlong (1), "H": Numberlong ("2174888517165095400"), "V": 2, "OP": "N", "NS" : "", "O": {"msg": "New Primary"}}

{"TS": Timestamp (1469180731, 1), "T": Numberlong (1), "H": Numberlong (" -1515174104405674576"), "V": 2, "OP": "C", "NS ":" admin. $cmd "," O ": {" create ":" System.version "}}

{"TS": Timestamp (1469180731, 2), "T": Numberlong (1), "H": Numberlong ("7948077691112953460"), "V": 2, "OP": "I", "ns" : "Admin.system.version", "O": {"_id": "Authschema", "CurrentVersion": 5}

{"TS": Timestamp (1469180731, 3), "T": Numberlong (1), "H": Numberlong (" -9003778602149648332"), "V": 2, "OP": "C", "NS ":" admin. $cmd "," O ": {" create ":" System.users "}}

{"TS": Timestamp (1469180731, 4), "T": Numberlong (1), "H": Numberlong (" -5105507245190417325"), "V": 2, "OP": "I", "NS ":" Admin.system.users "," O ": {" _id ":" ADMIN.BBB "," User ":" BBB "," DB ":" admin "," credentials ": {" Scram-sha-1 ": { "IterationCount": 10000, "salt": "9hpz67nn1d9zfskfxfpmhw==", "Storedkey": "wbvbdafg3tkpu0qwgoqa93xasfy=", "ServerKey ":" 0fxomrw01niiyr8hnz9p5mghk8k= "}," Roles ": [{" Role ":" Root "," db ":" Admin "}]}}

Rs1:primary>

To view the Oplog metadata information for master:

> Db.printreplicationinfo ()

To view the synchronization status of Salve:

> Db.printslavereplicationinfo ()

Rs1:primary> Db.printreplicationinfo () db.printreplicationinfo ()

Configured Oplog SIZE:2124.869140625MB

Log length start to End:315secs (0.09hrs)

Oplog First Event Time:fri 17:40:16 gmt+0800 (CST)

Oplog last event Time:fri Jul 17:45:31 gmt+0800 (CST)

Now:fri Jul 17:52:59 gmt+0800 (CST)

Rs1:primary> Db.printslavereplicationinfo () db.printslavereplicationinfo ()

source:localhost:28011

Syncedto:fri Jul 17:45:31 gmt+0800 (CST)

0 secs (0 hrs) behind the primary

source:localhost:28012

Syncedto:fri Jul 17:45:31 gmt+0800 (CST)

0 secs (0 hrs) behind the primary

Rs1:primary>

See the master-slave operation log in the MongoDB replication set Oplog