SATA Raid (stress test..)

[Beastie]

>
> 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