Date: Wed, 30 Aug 2017 20:35:13 -0400 From: William Dudley <wfdudley@gmail.com> To: Frank Leonhardt <frank2@fjl.co.uk> Cc: freebsd-questions <freebsd-questions@freebsd.org> Subject: Re: help creating new gmirror > 2TB Message-ID: <CAFsnNZ%2ByU-S1QBVJDrapy_N1mi3kUrHSbcbzNuDgTUceXwXPyA@mail.gmail.com> In-Reply-To: <26f5e88e-1ea7-6332-ca5e-f055cfbdd280@fjl.co.uk> References: <CAFsnNZLeuLYEJVozsoSvDtvgfMf4UueJhm37waOQ5_kyxs-rhg@mail.gmail.com> <26f5e88e-1ea7-6332-ca5e-f055cfbdd280@fjl.co.uk>
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I've never heard of AFD, and is having 4K sectors something I have control of? Or is tthat something the manufacturer controls? My drives are: 2 of Seagate 4TB IronWolf NAS SATA 6Gb/s NCQ 64MB Cache 3.5-Inch Internal Hard Drive (ST4000VN008) Which doesn't have the magic word "AFD" anywhere in the description. Also, I happen to like the idea of "fixing" the gmirror code to put it's metadata in the penultimate sector if it discovers GPT in the last sector, but I suppose I shouldn't get my hopes up. Bill Dudley On Wed, Aug 30, 2017 at 5:57 PM, Frank Leonhardt <frank2@fjl.co.uk> wrote: "I'm sure you'll be okay with MBR assuming it's an AFD (4K sector drive)." On 29/08/2017 21:12, William Dudley wrote: > >> Hi, >> >> I want to create a simple mirror > 2TB on a FreeBSD 10.3 system. >> >> I have 2 identical 4TB disks. >> >> The examples in freebsd handbook "geom-mirror" pages show creation of a >> 2TB >> mirror using >> MBR partitioning, and that has an upper limit of 2TB. >> > > I still get a bit worried about this, but I'm 99.9% sure you'll be okay > with MBR assuming it's an AFD (4K sector drive). The bodge/workaround > works. If it's SAS instead of SATA, all bets are off. > > Although I use ZFS a lot, I still prefer geom mirror for twin-disk > systems. I feel a lot more comfortable booting from it in the event of a > failure. ZFS has its good points, but so does UFS. > > Trying to get geom mirror to work with GPT as it stands just leads to > pain. I've taken a look at the code with a view to fixing this is no one > else does, but UFS is so un-cool in most circles and I don't fancy doing it > alone in case I zap someone's data. it doesn't look that tricky to move the > metadata somewhere else, and by checking for a GPT you can select between > the old/new block. It's unexpected interactions I'm worried about. > > I think we're safe with MBR until we pass 16Tb. > > Regards, Frank. > > > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe > @freebsd.org" >
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