Date: Mon, 18 Jul 2011 23:04:14 -0700 From: Kevin Oberman <kob6558@gmail.com> To: Jeremy Chadwick <freebsd@jdc.parodius.com> Cc: "freebsd-stable@freebsd.org Stable" <freebsd-stable@freebsd.org> Subject: Re: Status of support for 4KB disk sectors Message-ID: <CAN6yY1uaEwoEhEuoTNPqzywRaCPEvcLY-ddyFRUV00FcBDU1BA@mail.gmail.com> In-Reply-To: <20110718234124.GA5626@icarus.home.lan> References: <CAN6yY1uaUqk2ifiNViJyMFJWf60a4DmCiVs3Z=--_TjtzseABQ@mail.gmail.com> <20110718234124.GA5626@icarus.home.lan>
next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, Jul 18, 2011 at 4:41 PM, Jeremy Chadwick <freebsd@jdc.parodius.com> wrote: > On Mon, Jul 18, 2011 at 03:50:15PM -0700, Kevin Oberman wrote: >> I just want to check on the status of 4K sector support in FreeBSD. =A0I= read >> a long thread on the topic from a while back and it looks like I might h= it some >> issues if I'm not REALLY careful. Since I will be keeping the existing W= indows >> installation, I need to be sure that I can set up the disk correctly wit= hout >> screwing up Windows 7. >> >> I was planning on just DDing the W7 slice over, but I am not sure how we= ll this >> would play with GPT. Or should I not try to use GPT at all? I'd like >> to as this laptop >> spreads Windows 7 over two slices and adds a third for the recovery >> system, leaving >> only one for FreeBSD and I'd like to put my files in a separate slice. >> GPT would offer >> that fifth slice. >> >> I have read the handbook and don't see any reference to 4K sectors and o= nly a >> one-liner about gpart(8) and GPT. Oncew I get this all figured out, >> I'll see about writing >> an update about this as GPT looks like the way to go in e future. > > When you say "4KB sector support", what do you mean by this? =A0All > drives on the market as of this writing, that I've seen, all claim a > physical/logical sector size of 512 bytes -- yes, even SSDs, and EARS > drives which we know use 4KB sectors. =A0They do this to guarantee full > compatibility with existing software. > > Since you're talking about gpart and "4KB sector support", did you mean > to ask "what's the state of FreeBSD and aligned partition support to > ensure decent performance with 4KB-sector drives?" > > If so: there have been some commits in recent days to RELENG_8 to help > try to address the shortcomings of the existing utilities and GEOM > infrastructure. =A0Read the most recent commit text carefully: > > http://www.freebsd.org/cgi/cvsweb.cgi/src/sbin/geom/class/part/geom_part.= c > > But the currently "known method" is to use gnop(8). =A0Here's an example: > > http://www.leidinger.net/blog/2011/05/03/another-root-on-zfs-howto-optimi= zed-for-4k-sector-drives/ > > Now, that's for ZFS, but I'm under the impression the exact same is > needed for FFS/UFS. Jeremy, Yes, this is exactly what I mean. If I shell out for a high-end 7200 RPM drive for my laptop only to have it run like a dog. Thanks for the pointers. The first is good news. I'm a bit confused as to w= hat I will need gnop(8) for, but I'll be spending some time reading both the arti= cle and the gnop man page and hopefully that will make it clear. I've only used gpart once and to took way too long to figure out what I needed to do, but it did= work fine. I just wish FreeBSD had some decent documentation on such a fundament= al operation. Fortunately there are some pretty good articles folks have written, but they did leave me with several questions. --=20 R. Kevin Oberman, Network Engineer - Retired E-mail: kob6558@gmail.com
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAN6yY1uaEwoEhEuoTNPqzywRaCPEvcLY-ddyFRUV00FcBDU1BA>