6. Log Structured Storage

Introduction

Log-structured storage is a data organization and storage management approach that has gained significant traction in modern database systems. This method is designed to optimize write operations by treating the storage system as an append-only log, where new data is continuously added to the end of the log rather than updating data in place.

Key features of log-structured storage include:

1. Sequential writes: All data modifications are appended to the end of the log, resulting in high-performance write operations.

2. Immutability: Once data is written, it is not modified in place, which simplifies concurrency control and crash recovery.

3. Compaction: Periodic processes merge and compact log segments to reclaim space and improve read performance.

4. Efficient for write-heavy workloads: Particularly well-suited for systems with high write throughput requirements.

In this chapter, we'll explore the principles behind log-structured storage, its implementation in various database systems, and the trade-offs involved in adopting this approach. We'll also discuss how log-structured storage addresses challenges in traditional storage systems and its impact on overall database performance and reliability.

Understanding log-structured storage is crucial for database designers and administrators, as it offers innovative solutions to common storage management problems and has influenced the design of many modern database systems and distributed storage platforms.