Date: Mon, 23 Sep 2013 12:13:58 +0400 From: rozhuk.im@gmail.com To: "'Jia-Shiun Li'" <jiashiun@gmail.com>, "'Ravi Pokala'" <rp_freebsd@mac.com> Cc: freebsd-hackers@freebsd.org, freebsd-hardware@freebsd.org Subject: RE: What's the state of AF-4Kn support? Message-ID: <523ff852.4ee8cc0a.44b6.ffffacba@mx.google.com> In-Reply-To: <CAHNYxxNrMndF=s-s=YL4_7MNJ4ZENJ8YbVNzijOqo5XqZ2v2cw@mail.gmail.com> References: <CAHNYxxMZC7cw7TNBJMZewe3ABAS0S6Xaz%2BuDh2E_YbfP0fa2Pg@mail.gmail.com> <CE5F0282.F39EF%rpokala@mac.com> <CAHNYxxNrMndF=s-s=YL4_7MNJ4ZENJ8YbVNzijOqo5XqZ2v2cw@mail.gmail.com>
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# install gpart create -s GPT ada1 gpart show gpart add -i 1 -t freebsd-boot -b 40 -s 512 ada1 gpart add -i 2 -t freebsd-ufs -b 552 -s ..... ada1 gpart bootcode -b /boot/pmbr ada1 gpart bootcode -p /boot/gptboot -i 1 ada1 # for data gpart create -s GPT ada1 gpart show gpart add -i 1 -t freebsd-ufs -b 40 -s ..... ada1 > -----Original Message----- > From: owner-freebsd-hackers@freebsd.org [mailto:owner-freebsd- > hackers@freebsd.org] On Behalf Of Jia-Shiun Li > Sent: Monday, September 23, 2013 10:23 AM > To: Ravi Pokala > Cc: freebsd-hackers@freebsd.org; freebsd-hardware@freebsd.org > Subject: Re: What's the state of AF-4Kn support? > > On Wed, Sep 18, 2013 at 10:49 PM, Ravi Pokala <rp_freebsd@mac.com> > wrote: > > > > What you describe is the 'AF-512e' format - 4KB physical sectors > > *emulating* 512B logical sectors. See [ > > https://en.wikipedia.org/wiki/Advanced_Format#Advanced_Format_512e ; > > http://www.idema.org/?page_id=2153 ]. With AF-512e, yes, the HDD > > firmware does the read/modify/write for I/Os smaller than the > physical sector size. > > It is intended to be a low-cost/transitional format, allowing the HDD > > vendors to get the advantages of 4KB physical sectors (better error > > detection/correction algorithms, better areal density => lower cost) > > w/o breaking compatibility with decades of firmware and software that > > expect 512B logical sectors. > > > > What I'm asking about is AF-4kn - 4KB *logical* as well as physical > > sectors. All the enterprise HDD vendors have told us is that AF-4Kn > > drives expect data IO to be 4KB, and will reject smaller transfers. > > (*metadata* IO - SMART, IDENTIFY_DEVICE, READ_LOG/WRITE_LOG, etc - > > will remain 512B.) > > > > Doing some more digging, I found this post from ivoras which I missed > > the first time around [ > > http://ivoras.net/blog/tree/2011-01-01.freebsd-on-4k-sector- > drives.htm > > l ]; that tends to support my initial assessment - filesystem stuff > > should Just Work[tm] - plus adds the detail that direct drive I/O > (the > > example he gives is trying to `dd' 10 bytes) will be rejected because > > it is smaller than the raw-device access granularity. I've also > looked > > at 'ata_da.c' and see that adaregister() looks at both quirks and > > IDENTIFY_DEVICE data to determine the logical block size. > > > > So, that leaves the bootstrap code as the remaining question-mark. > > Does anyone what AF-4Kn support looks like there? > > > > CC -hackers. > > Thanks for the clarification. Is there any 4Kn HDDs shopping now? I am > not aware of any. > > BTW I believe UFS and ZFS have proper design for 4K-sectors, but > FreeBSD needs some ecosystem connections to get samples early to test, > incorporate supports and validate for it. Or we will need to wait until > it appears on market and someone got caught into some kind of bugs. > > Regards, > Jia-Shiun. > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers- > unsubscribe@freebsd.org"
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