Low HDD tranfer rate with FreeBSD 5.3-Release
hansot at iae.nl
Tue May 17 13:34:30 PDT 2005
[... dmesg snipped ...]
> 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.
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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
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