Date: Mon, 28 Dec 2009 12:58:24 +0100 From: Miroslav Lachman <000.fbsd@quip.cz> To: Alexander Motin <mav@FreeBSD.org> Cc: FreeBSD-Current <freebsd-current@freebsd.org>, Thomas Backman <serenity@exscape.org>, freebsd-arch@freebsd.org Subject: Re: File system blocks alignment Message-ID: <4B389D60.7000005@quip.cz> In-Reply-To: <4B34A183.7000909@FreeBSD.org> References: <4B349ABF.2070800@FreeBSD.org> <469FFFC8-514B-41B9-AEEC-E4B7AB6CB886@exscape.org> <4B34A183.7000909@FreeBSD.org>
next in thread | previous in thread | raw e-mail | index | archive | help
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. Miroslav Lachman
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4B389D60.7000005>