Date: Mon, 29 Jun 2009 10:38:53 +0100 From: Anton Shterenlikht <mexas@bristol.ac.uk> To: Marcel Moolenaar <xcllnt@mac.com> Cc: freebsd-current@freebsd.org, freebsd-questions@freebsd.org, freebsd-ia64@freebsd.org Subject: Re: gmirror gm0 destroyed on shutdown; GPT corrupt Message-ID: <20090629093853.GA44061@mech-cluster238.men.bris.ac.uk> In-Reply-To: <10FCC74D-6D46-4112-AD89-BBB4C5933957@mac.com> References: <20090625110253.GA31443@mech-cluster238.men.bris.ac.uk> <10FCC74D-6D46-4112-AD89-BBB4C5933957@mac.com>
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On Thu, Jun 25, 2009 at 09:41:13AM -0700, Marcel Moolenaar wrote: > > On Jun 25, 2009, at 4:02 AM, Anton Shterenlikht wrote: > > dev_taste(DEV,mirror/gm0) > > g_part_taste(PART,mirror/gm0) > > > > GEOM: mirror/gm0: the secondary GPT table is corrupt or invalid. > > GEOM: mirror/gm0: using the primary only -- recovery suggested. > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > You created the mirror after the GPT, which means you destroyed > the GPT backup header. gmirror uses the last sector on the disk > for metadata and that by itself is a cause for various problems. So, gmirror cannot be used on ia64 to mirror the boot disk? Because on ia64 the last sector always contains secondary GPT. I take it the RAID1 section, 19.4, in FBSD user manual, was written with i386 or alpha architecture in mind. > It's better to use gmirror per partition. how? Is it in the manual? any link? > > #echo 'geom_mirror_load="YES"' >> /boot/loader.conf > > Is /boot a symlink for /efi/boot? yes, lrwxr-xr-x 1 root wheel 8 Jun 25 10:44 boot -> efi/boot > > And when the system is rebooted, there is no /dev/mirror anymore. > > You could run into a race condition between GPT and gmirror and > GPT winning (again the result of gmirror using the last sector > on a disk for metadata). > > Alternatively, make sure gmirror got loaded at boot. # kldstat Id Refs Address Size Name 1 3 0xe000000004000000 ff9c08 kernel 2 1 0xe000000004ffa000 3c830 geom_mirror.ko # It's not that I desperately need to mirror a boot disk, it just that gmirror looked so easy in the manual, I wanted to give it a go. Perhaps I can just do a block copy to the second disk, say once a day, and have it as a backup. Could you also possibly comment on gvinum on ia64? many thanks anton -- Anton Shterenlikht Room 2.6, Queen's Building Mech Eng Dept Bristol University University Walk, Bristol BS8 1TR, UK Tel: +44 (0)117 928 8233 Fax: +44 (0)117 929 4423
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