一些Diskinfo參考數據

Hitachi 7K250 HDT722525DLA380
diskinfo -t /dev/ada2
/dev/ada2
        512             # sectorsize
        250059350016    # mediasize in bytes (233G)
        488397168       # mediasize in sectors
        484521          # Cylinders according to firmware.
        16              # Heads according to firmware.
        63              # Sectors according to firmware.
        VDS41BT4E553WJ  # Disk ident.

Seek times:
        Full stroke:      250 iter in   4.915525 sec =   19.662 msec
        Half stroke:      250 iter in   3.563548 sec =   14.254 msec
        Quarter stroke:   500 iter in   6.380010 sec =   12.760 msec
        Short forward:    400 iter in   1.936710 sec =    4.842 msec
        Short backward:   400 iter in   2.867826 sec =    7.170 msec
        Seq outer:       2048 iter in   0.267412 sec =    0.131 msec
        Seq inner:       2048 iter in   0.274978 sec =    0.134 msec
Transfer rates:
        outside:       102400 kbytes in   2.185484 sec =    46855 kbytes/sec
        middle:        102400 kbytes in   1.805673 sec =    56710 kbytes/sec
        inside:        102400 kbytes in   3.510185 sec =    29172 kbytes/sec

Hitachi 1tb HDT721010SLA360 on RAID1 with silicon image chip
/dev/ada1
        512             # sectorsize
        1000204886016   # mediasize in bytes (932G)
        1953525168      # mediasize in sectors
        1938021         # Cylinders according to firmware.
        16              # Heads according to firmware.
        63              # Sectors according to firmware.
        AL25744 38732452 0 S    # Disk ident.

Seek times:
        Full stroke:      250 iter in   1.626473 sec =    6.506 msec
        Half stroke:      250 iter in   3.714800 sec =   14.859 msec
        Quarter stroke:   500 iter in   2.971265 sec =    5.943 msec
        Short forward:    400 iter in   2.687425 sec =    6.719 msec
        Short backward:   400 iter in   2.871408 sec =    7.179 msec
        Seq outer:       2048 iter in   0.263439 sec =    0.129 msec
        Seq inner:       2048 iter in   0.271043 sec =    0.132 msec
Transfer rates:
        outside:       102400 kbytes in   1.069556 sec =    95741 kbytes/sec
        middle:        102400 kbytes in   1.265177 sec =    80937 kbytes/sec
        inside:        102400 kbytes in   1.890146 sec =    54176 kbytes/sec


Hitachi Deskstar 7K1000.B
Device Model:     Hitachi HDT721032SLA360
/dev/ada0
        512             # sectorsize
        320072933376    # mediasize in bytes (298G)
        625142448       # mediasize in sectors
        620181          # Cylinders according to firmware.
        16              # Heads according to firmware.
        63              # Sectors according to firmware.
        STF202MV0NJEBP  # Disk ident.

Seek times:
        Full stroke:      250 iter in   7.208919 sec =   28.836 msec
        Half stroke:      250 iter in   5.169054 sec =   20.676 msec
        Quarter stroke:   500 iter in   8.160034 sec =   16.320 msec
        Short forward:    400 iter in   1.952262 sec =    4.881 msec
        Short backward:   400 iter in   1.923025 sec =    4.808 msec
        Seq outer:       2048 iter in   0.226991 sec =    0.111 msec
        Seq inner:       2048 iter in   0.229122 sec =    0.112 msec
Transfer rates:
        outside:       102400 kbytes in   0.943371 sec =   108547 kbytes/sec
        middle:        102400 kbytes in   1.091681 sec =    93800 kbytes/sec
        inside:        102400 kbytes in   1.783073 sec =    57429 kbytes/sec