Your performance sucks because, to quote the manual, "Input data is
read and written in 512-byte blocks".
Try a sensible blocksize. 16k would mimic a standard file system
block, but even that is likely to underestimate. If you were, say,
copying the disk to another you could easily use 1Mb.
Some examples:
dd if=/dev/ad10s1a of=/dev/null
^C794830+0 records in
794830+0 records out
406952960 bytes transferred in 164.049297 secs (2480675 bytes/sec)
dd if=/dev/ad10s1a of=/dev/null bs=16k
^C53745+0 records in
53745+0 records out
880558080 bytes transferred in 21.092098 secs (41748245 bytes/sec)
So from 2Mb/s to 41Mb/s!
dd if=/dev/ad10s1a of=/dev/null bs=1m
^C933+0 records in
933+0 records out
978321408 bytes transferred in 13.836165 secs (70707556 bytes/sec)
And up to 70Mb/s though nothing real world is likely to achieve that.
There are a whole slew of ports (/usr/ports/benchmarks) some of which
do disk tests. I've used unixbench in the past, which is a bit of a
faff and does more than disks, but it works. If you run windows on
the box and want graphical benchtests, then there are free apps out
there that will do tests on disks, like Sandra.
--Alex
second tools is diskinfo, but i'm not quite happy with the result.
#diskinfo -t /dev/amrd0s1d
/dev/amrd0s1d
512 # sectorsize
999996609024 # mediasize in bytes (931G)
1953118377 # mediasize in sectors
121575 # Cylinders according to firmware.
255 # Heads according to firmware.
63 # Sectors according to firmware.
Seek times:
Full stroke: 250 iter in 5.233346 sec = 20.933 msec
Half stroke: 250 iter in 3.828152 sec = 15.313 msec
Quarter stroke: 500 iter in 6.232849 sec = 12.466 msec
Short forward: 400 iter in 2.409001 sec = 6.023 msec
Short backward: 400 iter in 2.594473 sec = 6.486 msec
Seq outer: 2048 iter in 0.638372 sec = 0.312 msec
Seq inner: 2048 iter in 0.671994 sec = 0.328 msec
Transfer rates:
outside: 102400 kbytes in 1.102065 sec = 92916 kbytes/sec
middle: 102400 kbytes in 1.209657 sec = 84652 kbytes/sec
inside: 102400 kbytes in 1.912485 sec = 53543 kbytes/sec
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