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From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no>
To: Alexander Motin <mav@FreeBSD.org>
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Date: Wed, 28 Apr 2010 09:35:17 +0200
In-Reply-To: <4BD6F797.5090205@FreeBSD.org> (Alexander Motin's message of
	"Tue, 27 Apr 2010 17:41:27 +0300")
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Cc: Maxim Sobolev <sobomax@FreeBSD.org>,
	FreeBSD-Current <freebsd-current@FreeBSD.org>,
	Richard Tector <richardtector@thekeelecentre.com>, freebsd-geom@FreeBSD.org
Subject: Re: Switchover to CAM ATA?
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Alexander Motin <mav@FreeBSD.org> writes:
> I haven't dug really deep into current ataraid(4), but AFAIK it is all
> done in software. At least there is no any offloading support on the
> controller drivers level. None of ata(4) drivers do anything except
> executing one ATA command at a time.

Correct.

That doesn't mean they *shouldn't* use offloading.

Like I said, I started working on checksum offloading for Promise SATA
controllers, but ZFS came along and I replaced the controllers because
of data corruption issues (which turned out to be either a driver bug or
a PCI timing bug which sos@ worked around in the driver, I forget which)

> Any URLs?

Google "Promise FastTrak SATA RAID"

I have two or three of those, including one with on-board SDRAM (but no
battery backup)

DES
--=20
Dag-Erling Sm=C3=B8rgrav - des@des.no