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Date:      Mon, 6 Dec 2010 20:35:36 +0100
From:      Ivan Voras <ivoras@freebsd.org>
To:        Pawel Jakub Dawidek <pjd@freebsd.org>
Cc:        svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org
Subject:   Re: svn commit: r216230 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs
Message-ID:  <AANLkTine9rGq_cM4ruFXYq=-F7cMXcQAr-zKHuWoQs2z@mail.gmail.com>
In-Reply-To: <20101206192238.GB1936@garage.freebsd.pl>
References:  <201012061218.oB6CI3oW032770@svn.freebsd.org> <20101206184453.GA1936@garage.freebsd.pl> <20101206192238.GB1936@garage.freebsd.pl>

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On 6 December 2010 20:22, Pawel Jakub Dawidek <pjd@freebsd.org> wrote:
> On Mon, Dec 06, 2010 at 07:44:53PM +0100, Pawel Jakub Dawidek wrote:
>> On Mon, Dec 06, 2010 at 12:18:03PM +0000, Ivan Voras wrote:
>> > Author: ivoras
>> > Date: Mon Dec =C2=A06 12:18:02 2010
>> > New Revision: 216230
>> > URL: http://svn.freebsd.org/changeset/base/216230
>> >
>> > Log:
>> > =C2=A0 Use GEOM stripesize field when calculating ashift. This will en=
able correct
>> > =C2=A0 alignment on drives with large sector sizes (e.g. 4 KiB) but th=
e
>> > =C2=A0 implementation might need to be revisited if devices with large=
 stripesizes
>> > =C2=A0 appear (e.g. if RAID controllers or flash drives start using th=
e field),
>> > =C2=A0 probably by introducing a physsectorsize field in GEOM provider=
s.
>>
>> Please back this out as soon as possible!
>>
>> > =C2=A0 Discussed with: mav, mostly silence on freebsd-geom@ and freebs=
d-fs@
>>
>> Guess why it wasn't picked up by anyone?
>
> In other words... Stop hack around. This is so irritating.
>
> If disk lies about its sector size, add quirks at the layer where disk
> is discovered. Don't hack ZFS, UFS, any other file system and GEOM
> classes, because its easiest for you. It would be best if you could just
> leave it to mav@ who knows this area and knows what he is doing. Those
> drive-by hacks of yours are really doing more evil than good.

I regard your personal opinion on this topic in little regard, as you
have too much of it.

Please persuade me on technical grounds why ashift, a property
intended for address alignment, should not be set in this way. If your
answer is "I don't know but you are still wrong because I say so" I
will respect it and back it out but only until I/we discuss the
question with upstream ZFS developers.

>From my POW, this is similar to changing UFS default fragment size to
match stripesize, which is a patch I also intend to commit (after a
review by mckusick, or course).



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