I’ll introduce how to change MongoDB LogLevel (log level) settings.

Set log level to maximum of 5

> use admin
switched to db admin

> db.adminCommand({setParameter:1, logLevel:5})
{ "was" : 0, "ok" : 1 }

Set log level to 1 to check queries

When you want to check Mongo queries, set the log level to 1.

> use admin
switched to db admin

> db.adminCommand({setParameter:1, logLevel:1})
{ "was" : 0, "ok" : 1 }

Set log level to minimum of 0

> db.adminCommand({setParameter:1, logLevel:0})
{ "was" : 5, "ok" : 1 }

Raising the log level will make the log file size extremely large and consume disk space, so don’t forget to return to an appropriate log level when log investigation is finished.

Reference Information

• 【CyberAgent】技術情報／TechReport - テックレポート／MongoDBの運用について | 株式会社サイバーエージェント

That’s all from the Gemba.