SAS Storage: High-Performance Hard Drives

Hitachi Ultrastar 15K450

The new Ultrastar 15K450 is Hitachi’s flagship 3.5” enterprise hard drive, running at 15,000 RPM. It is available with SAS/300 or Fibre Channel interfaces, and incorporates 16 MB of cache.

Like most other hard drives on the market, this unit utilizes perpendicular magnetic recording technology. Unlike the Seagate Cheetah 15K.6, the Ultrastar 15K450 does not come in capacities other than 450 GB—if you go for a 300 GB or 147 GB Ultrastar, that will be a 15K300, which does not offer the same performance. We added a 300 GB Ultrastar 15K300 to the benchmarks for your reference.

High Performance

The 5.9 ms average access time is slightly longer than the time taken by the new Seagate Cheetah 15K.6 to locate and access files, but it’s still an excellent result given 5.9 ms to 6.6 ms for comparable drives. We measured 191.7 MB/s interface bandwidth, far faster than the physical transfer rates, which reached 157 MB/s for reads and 140 MB/s for writes. Both are excellent results, and certainly faster than the sequential throughput you can get from flash SSDs, but Seagate’s Cheetah 15K.6 is even a bit faster.

The minimum throughput never drops below 98 MB/s on sequential writes, which provides an excellent basis for streaming applications and throughput-intensive servers. The high low-level performance also translates into excellent application benchmark results, although it cannot dominate the I/O benchmark section.