Log is an abstraction of system changes during the running process. The log content is a time-ordered collection of some operations and the corresponding 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.

Log group

A log group is a collection of logs and the basic unit for writing and reading.

Log topic

Logs in a Logstore can be classified by log topics. Users can specify the topic when writing a log, and must specify the log topic when querying logs.


A project is the Log Service's resource management unit, used to isolate and control resources. You can manage all the logs and the related log sources of an application by using projects. It manages all the Logstores of a user and configurations of log-collecting machines. It also serves as the portal by which users access the Log Service resources.


The Logstore is a unit in Log Service for the collection, storage, and query of log data.  Each Logstore belongs to a project, and each project can create multiple Logstores.


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.