# [[Introduction to logs]] Course:: [[Introduction to the Pillars of Observability]] ## Summary > [!abstract] Summary > Contents ## Log Logs - output messages as they are running - plain text files with a timestamp and events that have occurred Log aggregation can be a problem in [[Distributed computing]]. Logs should be stored in the cloud, accessible by all components and [[Grafana Loki]] - open source log aggregation system - stores aggregated logs in cloud storage ([[AWS Simple Storage Service (S3)]], [[Google Cloud Platform]] Storage, or [[Cassandra - LYT]]). - uses labels you specify to make searching logs efficient Logs-based Grafana commercial offerings - [[Grafana Enterprise Logs]] (GEL) - [[Grafana Cloud Logs]]