Ten years ago, it was common for database application development to take months or years. When databases were built, everything was worked out in advance: the database size, schema, number of users, and so on. Now database applications are developed over weeks or months, evolve during the process, and are put into production before all issues are fully understood.
This rapid deployment of mission-critical applications places rigorous demands on the storage engine, which needs to be highly available and have a fast recovery system and automatic management utilities.