Log is an abstraction of system changes during the runing process. The content is the time-ordered collection of some operations and operation results of specified objects. LogFile, Event, BinLog and Metric data are different carriers of logs. In LogFile, every log file is composed of one or more logs, and every log describes a single system event. A log is the minimum data unit processed in Log Service.
A log group is a collection of logs, and it is the basic unit for writing and reading.
Logs in the same Logstore can be grouped by log topics. You can specify the topic when writing a log, and specify the log topic when querying logs.
A project is the Log Service’s resource management unit that isolates and controls resources. You can use a project to manage all the logs and related log sources of one application. Projects manage Logstores and machine configurations of log collection. They also serve as the portal through which you can access Log Service resources.
A Logstore is the unit used in Log Service for log data collection, storage, and query. Each Logstore belongs to one project, and multiple Logstores can be created for a single project.
Each Logstore is divided into several shards and each shard is composed of an MD5 left-closed, right-open interval. These intervals do not overlap and the range of all intervals is the entire MD5 value range.