Storage Exhaustion from Unchecked Data Growth

critical

Resource ContentionUpdated Oct 1, 2017

When FreeStorageSpace drops below 10–15% of total allocated storage, the database risks running out of disk space entirely. This can cause write operations to fail, prevent transaction commits, and potentially corrupt data or crash the instance.

Sources

Monitoring RDS MySQL performance metrics | Datadogwww.datadoghq.com

Best practices for Amazon RDS - Amazon Relational Database Servicedocs.amazonaws.cn

Technologies:

MariaDBSymptoms of this issue are visible in MariaDB metrics and logs

Amazon RDSThe root cause of this issue originates in Amazon RDS

aws.rds.free_storage_space

aws.rds.write_iops

How to detect:

Monitor FreeStorageSpace metric continuously. Alert when it falls below 15% of total storage (AWS recommends action at 85% usage). Look for steady downward trend indicating uncontrolled growth. Correlate with write IOPS and table growth metrics.

Recommended action:

Immediately add more storage via the RDS console (storage can be increased but not decreased). Identify largest tables and indexes (INFORMATION_SCHEMA.TABLES) and archive or purge old data. Enable automatic storage scaling if available. Implement data retention policies and regular archival processes. Monitor binary log retention and purge old logs if not needed for replication.