Date: Mon, 06 Dec 2010 23:49:09 +0200 From: Alexander Motin <mav@FreeBSD.org> To: Ivan Voras <ivoras@freebsd.org> Cc: Bruce Cran <bruce@cran.org.uk>, 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: <4CFD5A55.5030702@FreeBSD.org> In-Reply-To: <AANLkTinPLsTa=S6pvxG55rK%2B3MBVRmKbha5bSZSN6w6G@mail.gmail.com> References: <201012061218.oB6CI3oW032770@svn.freebsd.org> <AANLkTine9rGq_cM4ruFXYq=-F7cMXcQAr-zKHuWoQs2z@mail.gmail.com> <20101206195327.GD1936@garage.freebsd.pl> <201012061518.49835.jhb@freebsd.org> <AANLkTi=Bnkq8sR3j7kq-aKzbk0TEd=kFiyr%2BqeQpzXGc@mail.gmail.com> <20101206211607.GA65110@muon.cran.org.uk> <AANLkTinPLsTa=S6pvxG55rK%2B3MBVRmKbha5bSZSN6w6G@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On 06.12.2010 23:22, Ivan Voras wrote: > On 6 December 2010 22:16, Bruce Cran<bruce@cran.org.uk> wrote: >> On Mon, Dec 06, 2010 at 09:31:39PM +0100, Ivan Voras wrote: >>> For what it's worth, apparently linux has the concept of "physical" >>> and "logical" sector sizes (possibly in addition to "stripe size"), >>> with physical being 4096 and logical 512, for example: >>> >>> # hdparm -I /dev/sde | grep size >>> Logical Sector size: 512 bytes >>> Physical Sector size: 4096 bytes >>> device size with M = 1024*1024: 1430799 MBytes >>> device size with M = 1000*1000: 1500301 MBytes (1500 GB) >> >> So do we, except they're both the same for Advanced Format drives: > > There is a subtle difference here which may be important. We have the > concepts of "sectorsize" and "stripesize". It is only question of abstraction. As soon as any our disk device is GEOM abstraction - don't see reason why parameters should be specific. > I think camcontrol actually reports logical and physical sector sizes > as reported by low-level drivers but currently GEOM names "logical > sector size" as "sectorsize" and "physical sector size" as > "stripesize". `camcontrol identify` directly requests IDENTIFY data and parses them. There is nobody between it and the device. To see what GEOM receives from the disk driver use diskinfo. > The term "stripesize" can be overloaded to mean both the item in > question - 4 KiB physical sector sizes and RAID stripe sizes. I think > this situation is bad and that the two meanings should be split. There could be a long list of different "stripesize" sources. It is not a task of the partitioning tool or file system to know all of them. As I have described in previous email - only size matters. >> # camcontrol identify /dev/ada1 >> ... >> device model WDC WD10EARS-00Z5B1 >> ... >> sector size logical 512, physical 512, offset 0 > > Agreed. Some drives lie. "Everybody lies". :) If Linux example was taken from page I've seen - it was external WD USB storage somehow reporting that physical sector size, not the disk itself. I haven't seen proper reporting in any WD drive yet (started to think about adding quirk at ada driver). Now waiting for Seagate 4K disks reports to check how bad things are. -- Alexander Motin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4CFD5A55.5030702>