Seagate ST3146707LW SAS and SATA: Multiple Benefits of Unified Storage (334K, - Page 2

SAS and SATA: Multiple Benefits of Unified Storage SAS Drives But the authors of the SAS standard wanted Advantage: Room to Grow something better; they had no intention of repeating the interface isolationism that had hamstrung parallel storage flexibility. And so compatibility with SATA became a central component of the SAS feature suite. This unified interface approach produces remarkable storage synergies and efficiencies, enabling IT professionals to achieve both their performance and capacity objectives with a single SAS infrastructure. Smaller companies with limited resources can save money by deploying a SAS infrastructure (HBAs, backplanes, cabling, and so forth) that is initially populated with low-cost, high-capacity SATA drives. As business expands and greater capacity is needed, more SATA drives can easily be added. With far greater scalability than a SATA infrastructure, a SAS infrastructure can connect over 16,000 SAS and/or SATA drives in one domain, ensuring vastly more room to grow than Advantages of Unified Storage The one-two punch of the SAS/SATA value proposition is simple: SAS hard drives deliver the speed, reliability and scalability demanded in high-availability enterprise environments, while high-capacity SATA drives are ideal for bulk storage applications, combining low cost per GB and greater reliability and scalability than their parallel ATA ancestors. Complementary by design, SAS boasts the best performance/dollar while SATA offers maximum capacity/dollar. The advantages of SAS/SATA compatibility benefit every sector of the storage landscape, from burgeoning firms with modest needs (and budgets to match) to vast Fortune 100 enterprises with a complex mix of transactional and reference data storage requirements. Savvy system builders and integrators have been quick to recognize even the beleaguered IT departments of today typically require. A SAS infrastructure can easily support a multitude of SATA drives with a single SAS HBA port. As more SATA drives and SAS RAID backplanes are added to a storage enclosure, SAS expanders on those backplanes can be seamlessly cascaded together. Requiring only a minimal number of ports on the HBA, and with more ports available on the expanders, a SAS infrastructure becomes increasingly cost effective as the number of drives rises. When these growing firms move further into online/transactional applications (entailing critical data with high availability to multiple, concurrent users), adding high-performance SAS drives is literally a snap, with zero modifications of the existing infrastructure required. the unique blend of performance, capacity and flexibility advantages that a SAS infrastructure can deliver to their customers. SAS 3.5-inch System Backplane SAS for Performance, SATA for Capacity SATA Drives Device SAS (15K RPM, 10K RPM) SATA (7200 RPM) Application Work Environment Performance-intensive, high availability, random reads 24 hrs/day 7 days/week Capacity-intensive, low availability, 8 hrs/day sequential reads 5 days/week Seek Time (typical) 3.5 ms (15K RPM); 3.9 ms (10K RPM) 9.5 ms Figure 1. Combining SATA with SAS in a unified storage system ensures ultimate application support. Server SAS RAID Controller Expander Expander Expander Expander Expander Figure 2. SAS infrastructure delivers exceptional expandability and flexibility by enabling direct cascading of multiple expanders.