Date: Mon, 28 Dec 2009 14:30:22 +0200 From: Alexander Motin <mav@FreeBSD.org> To: Miroslav Lachman <000.fbsd@quip.cz> Cc: FreeBSD-Current <freebsd-current@freebsd.org>, Thomas Backman <serenity@exscape.org>, freebsd-arch@freebsd.org Subject: Re: File system blocks alignment Message-ID: <4B38A4DE.2040507@FreeBSD.org> In-Reply-To: <4B389D60.7000005@quip.cz> References: <4B349ABF.2070800@FreeBSD.org> <469FFFC8-514B-41B9-AEEC-E4B7AB6CB886@exscape.org> <4B34A183.7000909@FreeBSD.org> <4B389D60.7000005@quip.cz>
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Miroslav Lachman wrote: > Alexander Motin wrote: >> Thomas Backman wrote: >>> On Dec 25, 2009, at 11:58 AM, Alexander Motin wrote: >> |>> Recently WD released first series of ATA disks with increased >> physical >>>> sector size. It makes writes not matching with 4K blocks inefficient >>>> there. >>> They don't expose this to the OS, though (not by default, anyway), >>> but chop it up into 8 512-byte sectors for compatibility reasons. >>> Just thought I'd point that out - I'm not even sure if you can get >>> them to *not* do the compatibility thing and expose 4k-sized sectors. >> >> Latest ATA-8 specification allows drive to report both logical (512B) >> and physical (4KB) sector sizes. ada driver able to fetch and report >> that info to GEOM. If these drives not reporting it yet (are you really >> sure?), it is only question of their firmware. > > There is an article about 4k sectors > http://www.anandtech.com/storage/showdoc.aspx?i=3691 > > It is completely hidden to OS in first versions. Thanks for the link, but all I see there is "but at this point there’s no such tool". IMHO it doesn't meet it is not reported. We just need somebody with that drive to run on it `camcontrol identify` from the fresh system and report what he sees. -- Alexander Motin
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