Date: Mon, 23 Jan 2012 12:43:06 -0800 From: Freddie Cash <fjwcash@gmail.com> To: Steven Hartland <killing@multiplay.co.uk> Cc: freebsd-stable@freebsd.org Subject: Re: ZFS: i/o error - all block copies unavailable on large disk number machines Message-ID: <CAOjFWZ79eDXBsWStDMbKsS9uW6gzU_4oMLDwf65GOUfjeDJ4=A@mail.gmail.com> In-Reply-To: <DEEB03C635054C428B91955C58EA21D3@multiplay.co.uk> References: <520B9285BCC0498286196195933D67E9@multiplay.co.uk> <CB4ED392-3DED-40C1-83B0-7DB3B9C612C0@mac.com> <DEEB03C635054C428B91955C58EA21D3@multiplay.co.uk>
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On Mon, Jan 23, 2012 at 11:21 AM, Steven Hartland <killing@multiplay.co.uk> wrote: > Not something I've seem made clear, but quite possibly. Even with > 9 disks you could easily get this if the BIOS doesn't see all of > said disks, be that initially or due to disks added to the machine. > > For reference the original install was done on a zpool with 6 disks > in a raidz2 config but then 6 additional disks where added to expand > capacity. > > It was only when the new kernel was installed that data required > to boot was then written to disks in the seconds raidz2 which is > inaccessible to the boot code even though in perfect working order > on a booted system. > > So something to document, watch out for and potentially safe > guard against? > > It maybe something specific to machines with legacy BIOS hence not > an issue with Sun kit? >From what I've gathered on the zfs-discuss mailing list, Solaris only supports rpool's (bootable pool) to use mirror vdevs, and only a single vdev in the rpool. FreeBSD is (AFAIK) the only ZFS implementation that supports booting from a raidz vdev, and from a pool with multiple raidz vdevs. IME, separating the bootable disks from the storage disks will always save you time, effort, and grief in the long run. :) Whether that means using a separate UFS / filesystem, or a mirrored set of disks for /, or a separate ZFS pool with a single mirror vdev is up to the admin. But boot/OS should be separate from bulk storage. :) -- Freddie Cash fjwcash@gmail.com
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