Low HDD tranfer rate with FreeBSD 5.3-Release

[Hans Ottevanger]

Amandeep wrote:

[... dmesg snipped ...]

> A
> Eric Anderson wrote:
>
>> Amandeep wrote:
>>
>>> Hi all,
>>>
>>> I am using Tyan S2098 MB with 160GB Maxtor ATA  Drive and the 
>>> transfer rate is very low. FreeBSD 5.3-Release.
>>> Any ideas what is going on here.
>>>
>>> The transfer rate is about 15MB/s
>>>
>>> when I run
>>> #dd if=/dev/zero of=/usr/junk bs=8192
>>>
>>> then do
>>> #iostat 1
>>
>>
>>
>> You should probably provide the appropriate information from dmesg 
>> output, along with what you expect it to be, and the outputs of the 
>> dd command.
>>
>> Eric
>>
>>
>>
>
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Hi,

I had practically the same problem, i.e. the same very low ATA write 
speed, with very similar hardware (ASUS P533-E, same chipset and CPU as 
yours). This occurred with both 5.3-STABLE and 5.4-STABLE.

I found that the problem disappears when I disable atapi_dma in the 
loader (or with 5.4, do not enable it). Alternatively, I can use 
"atacontrol mode 0 UDMA100" to force the ATA channel for the harddisk to 
UDMA100. I do not know why this works though, I still need some closer 
investigation. Something weird in the ATA driver must be going on.

Anyhow, my HDD (WD-1200JB) is up-to-speed now, -45Mbytes/s reading AND 
writing.

Kind regards,

Hans