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Date: Mon, 13 Dec 2004 21:22:35 +0200
From: Maxim Sobolev <sobomax@portaone.com>
Organization: Porta Software Ltd
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To: Poul-Henning Kamp <phk@phk.freebsd.dk>
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cc: "current@freebsd.org" <current@freebsd.org>
Subject: Re: GBDE write performance really sucks
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Maxim Sobolev wrote:
> Poul-Henning Kamp wrote:
> 
>> In message <41BB0305.7000206@portaone.com>, Maxim Sobolev writes:
>>
>>> Hi Poul,
>>>
>>> I have noticed that GBDE write performance is very low, even on 
>>> modest hardware (3.2 P4 with 1MB cache and 7200 IDE HDD):
>>
>>
>>
>> Which logical sectorsize did you use ?
> 
> 
> 2KB.

Little more investigation revealed that the problem was due to disabled 
write cache in ata(4). It would be interesting to compare FreeBSD 
behaviour to behaviour of other operating systems in such situation, 
since the drop of sequental writing performance in the case of 8KB 
blocks and disabled write cache in FreeBSD is about 20x (from more than 
20MB/sec to merely 1MB/sec), which doesn't look reasonably to me.

-Maxim