Date: Thu, 1 Apr 2010 18:36:43 +0200 From: Olivier Smedts <olivier@gid0.org> To: Bartosz Stec <bartosz.stec@it4pro.pl> Cc: freebsd-fs@freebsd.org, freebsd-current@freebsd.org Subject: Re: gpart failing with no such geom after gpt corruption Message-ID: <r2t367b2c981004010936o52837211j8dc8d62ce128d612@mail.gmail.com> In-Reply-To: <4BB49E3F.7070506@it4pro.pl> References: <4BB49E3F.7070506@it4pro.pl>
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2010/4/1 Bartosz Stec <bartosz.stec@it4pro.pl>: > Hello ZFS and GPT hackers :) > > I'm sending this message to both freebsd-current and freebsd-fs because i= t > doesn't seems to be a CURRENT-specific issue. > > Yesterday I tried to migrate my mixed UFS/RAIDZ config to clean RAIDZ wit= h > GPT boot. I've following mostly this guide: > http://wiki.freebsd.org/RootOnZFS/GPTZFSBoot/RAIDZ1 > I'm using CURRENT on 3x40GB HDDs (ad0-ad3) and additional 250GB HDD has b= een > used for data migration (ad4). > > Data was copied form RAIDZ to 250GB HDD, GPT sheme was created on =A040GB > HDDs, then new zpool on them, and finally data went back to RAIDZ. Bootin= g > from RAIDZ was succesful, so far so good. > > After a while I've =A0noticed some SMART errors on ad1, so I've booted ma= chine > with seatools for dos and made long test. One bad sector was found and > reallocated, nothing to worry about. > As I was in seatools already, I've decided to adjust LBA size on that dis= k > (seatools can do that), because it was about 30MB larger than the other t= wo, > and because of that I had to adjust size of freebsd-zfs partition on that > disk to match exact size of others (otherwise 'zpool create' will complai= n). > So LBA was adjusted and system rebooted. > > Yes, I was aware that changing disk size probably end with corrupted GPT = and > data loss, but it doesn't seem to be a big deal for me as far as 2/3 of > zpool is alive, because I can always recreate gpt and resilver ad1. > > Unfortunately it wasn't so easy. First of all system booted, and as I > expected kernel message shows GPT error on ad1. Zpool was degraded but al= ive > and kicking. However, when I tried to execute any gpart command on ad1, i= t > return: > > =A0 ad1: no such geom Are you sure you created a partition scheme with gpart on ad1 before issuing partition-related gpart commands ? > > ad1 was present under /dev, and it could be accessed by sysinstall/fdisk, > but no with gpart. I've created bsd slice with sysinstall on ad1 and > rebooted, with hope that after reboot I could acces ad1 with gpart and > recreate GPT scheme. Another surprise - system didn't boot at all, reboot= ing > after couple of seconds in loader (changing boot device didn't make a > difference). > > Only way I could boot system at this moment was connecting 250GB HDD whic= h > fortunately still had data from zpool migration and boot from it. Another > surprise - kernel was still complaining about GPT corruption on ad1. I ha= d > no other ideas so I ran > > =A0 dd if=3D/dev/zero of=3D/dev/ad1 bs=3D512 count=3D512 > > to clear beginning of the hdd. After that disk was still unaccesible from= t > gpart, so I tried sysinstall/fdisk againt to create standard BSD > partitioning scheme and rebooted system. > After that finally gpart started to talk with ad1 and GPT scheme and zpoo= l > has been recreated and work as it supposed to. > > Still, how can we clear broken GPT data after it got corrupted? > Why gpart has been showing "ad1: no such geom", and how can we deal with > this problem? > Finally, why gptzfsboot failed with GPT corrupted on other disk after try= ing > to fix it, while it booted at first place? > > Or maybe changing LBA size of already partitioned HDD is extreme case, an= d > the only way these problems could be triggered ;)? > > Cheers! > > -- > Bartosz Stec > > > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" > --=20 Olivier Smedts _ ASCII ribbon campaign ( ) e-mail: olivier@gid0.org - against HTML email & vCards X www: http://www.gid0.org - against proprietary attachments / \ "Il y a seulement 10 sortes de gens dans le monde : ceux qui comprennent le binaire, et ceux qui ne le comprennent pas."
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