HP 504062-B21 Performance factors for HP ProLiant Serial Attached Storage (SAS - Page 13

SAS drive specifications Table 3 compares the seek time and power consumption of SFF (2.5-inch) SAS drives available from HP at time of publication. NOTE: Drive types and specifications are subject to change without notice. Refer to the following site for a listing and specifications of currently available SAS drives: http://h18004.www1.hp.com/products/servers/proliantstorage/ serial/sas/index.html Table 3. Comparison of seek time and power consumption of HP SFF SAS drives Capacity/RPM Seek time: Single track Average Full stroke Power consumption: Idle Maximum 36 GB/15K 0.20 ms 3.0 ms 7.0 ms 5.74 watts 7.25 watts 72 GB/10K 0.20 ms 4.0 ms 8.1 ms 5.96 watts 8.42 watts 72 GB/15K 0.20 ms 3.0 ms 7.0 ms 6.11 watts 8.29 watts NOTE: All drives listed In Table 3 have a cache/buffer size of 16 MB and a transfer time of 3 Gb/s. 146 GB/10K 0.60 ms 4.1 ms 8.0 ms 6.31 watts 8.73 watts Conclusion A variety of hard drive types are used in today's server industry. The right HDD type is the one that provides the best return on investment (ROI) for a particular server application. Small-to-medium businesses (SMBs) or environments with less-than-demanding applications can be well served with SCSI or SATA drives that offer economical service and good dollar-per-gigabyte value. 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, higher drive densities per U space can be achieved without a significant increase in power consumption. Higher drive densities provide better overall performance, reliability, and lower operating costs. 13