Date: Fri, 21 Nov 2014 16:00:56 -0700 (MST) From: Warren Block <wblock@wonkity.com> To: Nathan Whitehorn <nwhitehorn@freebsd.org> Cc: Rostislav Krasny <rosti.bsd@gmail.com>, freebsd-sysinstall@freebsd.org Subject: Re: Dangerously dedicated mode with FreeBSD 10.1 Message-ID: <alpine.BSF.2.11.1411211556560.27494@wonkity.com> In-Reply-To: <546FBEC0.500@freebsd.org> References: <CANt7McFwQJNmBEJGTed%2B27K%2BVAY80V1zJSXBwHC0TmrX1iyPpw@mail.gmail.com> <alpine.BSF.2.11.1411210815470.12278@wonkity.com> <546F6D79.9060909@freebsd.org> <alpine.BSF.2.11.1411211527040.27494@wonkity.com> <546FBEC0.500@freebsd.org>
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On Fri, 21 Nov 2014, Nathan Whitehorn wrote: >>> This has never been true. It does 4K alignment on disks with 4K physical >>> sectors (no matter what the logical sector size is). If you have disks >>> with larger sectors or preferred boundaries (e.g. a striped RAID), it will >>> also align to that. >> >> I know that it did not automatically do that alignment originally, which >> was why I entered PR 161720: >> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=161720 >> >> After that, I thought it was fixed, and now this appears to be a >> regression: >> http://forums.freebsd.org/threads/does-bsdinstall-in-10-1-properly-partition-ssds.48993/ >> > > It has done this since initially committed to the tree before 9.0. If you > have a drive with 512 byte physical sectors, it will use 512 byte alignment. > If you have a 4K drive, it will use 4K alignment. Is there anywhere in those > threads where it misaligns a partition? Most of the discussion just seems to > be that it does use 512 byte alignment sometimes, which isn't an issue if you > have 512 byte sectors. This might be an "Advanced Format" thing, where the drive uses 4K sectors but reports that it uses 512-byte sectors. The forum thread shows that it does not align to 4K on SSDs. My SSDs also report 4K stripesize but only 512 byte sectoresize.home | help
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