Benefits And Best Practices For Deploying SSDS In An OLTP Environment Using Dell Equallogic PS Series

By Dell Inc.

Using Solid State Disks (SSDs) in enterprise storage arrays is one of today's hottest storage trends. Mechanical hard disk drives (HDDs) with a cache memory-based front-end in the disk array controller have been the dominant I/O architecture for high-end application data storage until now. However, with increasing capacities and falling prices of memory chips, and the growing number of performance-hungry applications, many storage vendors have introduced SSDs in their disk arrays to improve application performance. Moreover, since SSDs can consume significantly less power than HDDs, they also help reduce energy consumption in power-hungry data centers.

SSDs add another tier (Tier-0) to the application storage architecture. Although currently limited in capacity, SSDs can offer up to an order-of-magnitude IOPS improvement over HDDs. However, real-world, latency-sensitive applications such as banking, electronic trading, web searching, and online reservation systems do not benefit equally from the higher IOPS performance of SSDs. Workload-specific I/O characteristics dictate the performance benefits an application can gain from SSDs. To demonstrate the benefit of SSD arrays with real-world applications, Dell Labs tested the capabilities of SSDs using an Online Transaction Processing (OLTP) workload. The database was implemented in a tiered storage model that includes the latest Dell EqualLogic™ PS6000 arrays with SAS HDD and SSD drives. Dell Labs conducted multiple tests by moving various database elements (including logs, temporary files and data objects) from HDD to SSD drives and measuring the performance deltas. These tests demonstrate that in an EqualLogic iSCSI SAN, depending on your user load, latency-sensitive OLTP database applications can expect up to an estimated 75% increase in transaction throughput or up to a 60% improvement in response times by isolating and moving read-intensive datasets from SAS drives to SSD drives as compared to moving the same datasets to additional SAS drives.