Someone

db@desktop:/home/db> sudo diskinfo -t /dev/mirror/gm0
        512             # sectorsize
        320072932864    # mediasize in bytes (298G)
        625142447       # mediasize in sectors

Seek times:
        Full stroke:      250 iter in   1.467916 sec =    5.872 msec
        Half stroke:      250 iter in   1.469573 sec =    5.878 msec
        Quarter stroke:   500 iter in   2.953513 sec =    5.907 msec
        Short forward:    400 iter in   2.500432 sec =    6.251 msec
        Short backward:   400 iter in   2.482748 sec =    6.207 msec
        Seq outer:       2048 iter in   0.152792 sec =    0.075 msec
        Seq inner:       2048 iter in   0.160324 sec =    0.078 msec
Transfer rates:
        outside:       102400 kbytes in   1.357092 sec =    75455 kbytes/sec
        middle:        102400 kbytes in   1.558013 sec =    65725 kbytes/sec
        inside:        102400 kbytes in   2.644098 sec =    38728 kbytes/sec

db@desktop:/home/db>