Performance factors for HP ProLiant Serial Attached Storage (SAS)

Table 3. Comparison of seek time and power consumption of HP SFF SAS drives

Capacity/RPM 36 GB/15K 72 GB/10K 72 GB/15K 146 GB/10K

Seek time:

Single track

Average

Full stroke

0.20 ms

3.0 ms

7.0 ms

0.20 ms

4.0 ms

8.1 ms

0.20 ms

3.0 ms

7.0 ms

0.60 ms

4.1 ms

8.0 ms

Power

consumption:

Idle

Maximum

5.74 watts

7.25 watts

5.96 watts

8.42 watts

6.11 watts

8.29 watts

6.31 watts

8.73 watts

All drives listed In Table 3 have a cache/buffer size of 16 MB and a transfer time of 3 Gb/s.

Conclusion

Today’s server industry uses a variety of hard drive types. The right HDD type is the one that provides

the best return on investment for a particular server application. Economical service and good dollar-

per-gigabyte value SATA drives offer the best value to small-to-medium businesses or environments

with less-than-demanding applications.

In the mission-critical, performance-oriented, enterprise server environment where hard drive duty

cycle is 100 percent, SFF SAS drives excel in performance and reliability. Since SFF drives require

only 70 percent of the space and half the power of 3.5-inch drives, users can achieve higher drive

densities per U space without a significant increase in power consumption. Higher drive densities

provide better overall performance, reliability, and lower operating costs.