siis/atacam/ata/gmirror 8.0-BETA3 disk performance

[Olivier Smedts]

2009/9/2 Emil Mikulic <emikulic at gmail.com>:
> On Wed, Sep 02, 2009 at 08:04:04AM -0400, Derek (freebsd lists) wrote:
>> Hi,
>>
>> I've been testing the new siis driver, and I have found no
>> appreciable performance change, using dd as a measure of "raw"
>> performance.
>>
>> I get about 40MB/s read, and 30MB/s write.  See attached
>> bench-*.txt files.
>
> [...]
>
>> ada0: <ST31500341AS CC1H> ATA/ATAPI-8 SATA 2.x device
>> ada0: 1430799MB (2930277168 512 byte sectors: 16H 63S/T 16383C)
>
> Huh, I have the same disk:
>
> # dmesg | grep ad4
> ad4: 1430799MB <Seagate ST31500341AS CC1H> at ata2-master SATA300
>
> Sequential read on a disk this size should be around 120MB/sec at the
> outer tracks:
>
> # dd if=/dev/ad4 of=/dev/null bs=128k count=5000
> 655360000 bytes transferred in 5.171389 secs (126728039 bytes/sec)
>
>> Also I find it surprising that my gmirror read is only 40MB/s,
>> and not 60-80MB/s, any thoughts on this?
>
> Stripe will give you higher throughput.
> Mirror will give you more random seeks per second.

And higher read throughput.

>
> --Emil
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-- 
Olivier Smedts                                                 _
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