An In-depth Exploration of SSD Performance

Introduction

Solid State Drives (SSDs) have become increasingly popular in the field of storage due to their superior performance compared to traditional Hard Disk Drives (HDDs). This article aims to delve deep into the performance aspects of SSDs.

Key Concepts in SSD Performance

1. FOB (Fresh Out of Box): When an SSD is freshly unpacked, its performance is at its peak, similar to a person in a state of intense anger with maximum power but not sustainable.
2. Transition: After some period of reading and writing, the performance gradually declines and approaches a stable state.
3. Steady State: The performance stabilizes within a certain range. Performance-related data such as Throughput, IOPS, and Latency must be obtained in this state to accurately assess the quality of the SSD.

SSD Performance Test Procedures

1. Purge the device: This is to eliminate the influence of previous operations before the performance test, ensuring the SSD starts from a known and consistent state.
2. Run Workload Independent Precondition: For example, write the SSD twice with a 128K block size sequence.
3. Run Test: Set relevant parameters such as OIO/Thread, Thread count, and Data Pattern to start the Workload Dependent Precondition. If the Steady Status is reached within 25 rounds, specific measurement intervals are determined.

Performance Test Items for SSDs

The performance tests for SSDs include IOPS testing, Throughput testing, Latency testing, and optional saturated write testing.

SSD Performance in Different Brands

1. Intel: In the VMworld conference, it was shown that NVMe SSD can achieve high IOPS in vSAN architectures.
2. Samsung: Samsung SSDs are renowned for their excellent read and write speeds. The NVMe SSDs like the 970 EVO and 980 series offer high sequential and random read and write performances.
3. Hikvision: Hikvision SSDs also perform well in terms of read and write speeds, random read and write performance, IOPS, reliability, and durability.

Factors Affecting SSD Performance Decline

One of the main reasons for the decline in SSD performance over time is the need for Garbage Collection (GC). When new data needs to be written and there is insufficient free space, SSD has to perform GC operations, which consume part of its performance.

Conclusion

Understanding SSD performance requires a comprehensive grasp of key concepts, test procedures, and factors influencing it. By analyzing these aspects, users can make more informed decisions when choosing and using SSDs.