What data will be available in the DDS instance space
Service data generated on the application side takes up major instance space.
Database system data, including metadata and index data.
Log data, such as journal logs, oplog logs, and rollback logs.
What logs and files occupy DDS disk space
Log files mainly include mongod.log, journal log, and mongos.log.
Files include business data files, index files, and database configuration files.
Why is the disk usage displayed on the page smaller than the actual usage
DDS compresses the data and stores it on disk, so it may appear smaller than the actual size.
Data is deleted but disk space is not reduced
DDS uses WiredTiger as the default storage engine. When the WiredTiger engine deletes data, it doesn't immediately release the disk space, but use this space for writing new data, which will not affect the disk utilization.
The purchased database instance is 8 GB, why is the resident memory only about 4 GB instead of 8 GB
This is because the operating system and monitoring processes take up some of the actual memory, resulting in the resident memory being smaller than the actual memory purchased.