MongoDB复制集APS架构问题(writeConcern)

当前数据库采用APS架构(主、从、仲裁)，考虑对服务器进行迁移，迁移从库时，主库无法写入

查看应用链接配置发现端倪

mongo复制集从库关机，对write-concern参数进行测试

[mongo@Mon02 ~]$ mongo
MongoDB shell version v4.4.16
connecting to: mongodb://127.0.0.1:27017/?compressors=disabled&gssapiServiceName=mongodb
Implicit session: session { "id" : UUID("265bba7f-21bf-496d-942d-fd904127ee09") }
MongoDB server version: 4.4.16
MongoRepl:SECONDARY> use admin
switched to db admin
MongoRepl:SECONDARY> db.auth("admin","cpcn1234")
1
MongoRepl:SECONDARY> db.shutdownServer()
server should be down...
>

测试writeConcern各参数现象

MongoRepl:PRIMARY> db.test.insert({name:'test9'},{writeConcern:{w:'majority',wtimeout:6000}})
WriteResult({
        "nInserted" : 1,
        "writeConcernError" : {
                "code" : 64,
                "codeName" : "WriteConcernFailed",
                "errmsg" : "waiting for replication timed out",
                "errInfo" : {
                        "wtimeout" : true,
                        "writeConcern" : {
                                "w" : "majority",
                                "wtimeout" : 6000,
                                "provenance" : "clientSupplied"
                        }
                }
        }
})

w:‘majority’，6秒后返回错误

MongoRepl:PRIMARY> db.test.insert({name:'test7'},{writeConcern:{w:0}})
WriteResult({ })

w:0，可正常写入

MongoRepl:PRIMARY> db.test.insert({name:'test5'},{writeConcern:{w:1}})
WriteResult({ "nInserted" : 1 })

w:1，可正常写入

MongoRepl:PRIMARY> db.test.insert({name:'test8'},{writeConcern:{w:2,wtimeout:6000}})
WriteResult({
        "nInserted" : 1,
        "writeConcernError" : {
                "code" : 64,
                "codeName" : "WriteConcernFailed",
                "errmsg" : "waiting for replication timed out",
                "errInfo" : {
                        "wtimeout" : true,
                        "writeConcern" : {
                                "w" : 2,
                                "wtimeout" : 6000,
                                "provenance" : "clientSupplied"
                        }
                }
        }
})

w:2，6秒后返回错误

报错时日志信息

关键字 “Slow query”，“writeConcern”

more /mongodb/mongod.log
{"t":{"$date":"2022-08-30T13:50:01.621+08:00"},"s":"I",  "c":"COMMAND",  "id":51803,   "ctx":"conn58","msg":"Slow query","attr":{"type":"command","ns":"test.test","appName":"MongoDB Shell","command":{"insert":"test","ordered":true,"writeConcern":{"w":2.0,"wtimeout":6000.0},"lsid":{"id":{"$uuid":"55eb7aad-324a-41dc-9f41-aa213628acec"}},"$clusterTime":{"clusterTime":{"$timestamp":{"t":1661833513,"i":2}},"signature":{"hash":{"$binary":{"base64":"9GLSLDyutIlwuTiqCOKrKWwrQmU=","subType":"0"}},"keyId":7136548260675584003}},"$db":"test"},"ninserted":1,"keysInserted":1,"numYields":0,"reslen":439,"locks":{"ParallelBatchWriterMode":{"acquireCount":{"r":1}},"FeatureCompatibilityVersion":{"acquireCount":{"w":1}},"ReplicationStateTransition":{"acquireCount":{"w":1}},"Global":{"acquireCount":{"w":1}},"Database":{"acquireCount":{"w":1}},"Collection":{"acquireCount":{"w":1}},"Mutex":{"acquireCount":{"r":1}}},"flowControl":{"acquireCount":1,"timeAcquiringMicros":2},"writeConcern":{"w":2,"wtimeout":6000,"provenance":"clientSupplied"},"storage":{},"protocol":"op_msg","durationMillis":6019}}