On 03/01/2010 07:41 PM, Benjamin Scott wrote: > On Mon, Mar 1, 2010 at 5:48 PM, Jerry Feldman <g...@blu.org> wrote: > >> pe_align (128 sectors) must not be less than pe_align_offset >> (36028797018963967 sectors) >> > By my calculations, the second number of sectors works out to 16 > million terabytes, which makes me suspect the diagnostic itself is > broken, or being fed broken data. > > >> Nore that /dev/md1 is formatted ext4. >> > Are you trying to import an ext4 filesystem into LVM "in place"? If > so, that won't work. You have to create a new (empty) LV (Logical > Volume) and copy the filesystem into the LV. You can do the copy in > any number of ways, but mounting both and doing "cp -a" generally > works. > > If you just want to use /dev/md1 as a new empty PV (Physical > Volume), then try erasing the filesystem superblock on /dev/md1 so LVM > thinks it is blank. > > WARNING: The following command will destroy all data on the filesystem! > > dd if=/dev/zero of=/dev/md1 bs=512 count=1 > > WARNING: The preceding command will destroy all data on the filesystem! > > (I know you know what "dd if=/dev/zero" does; the warnings are for > other readers. (Who also don't care about data remanence.)) > > You can't do an in-place import of a filesystem to an LV because LVM > LVs are structured entities which are not always linear, and LVM PVs > contain metadata at the start (and maybe also the end), neither of > which are how filesystems see block devices. There are probabbly > cases where it would be doable in theory, but I don't think anyone's > bothered with code. > > >> What I am trying to do is to migrate my system (LVM on /dev/sda2) to raid1. >> > I'm not sure if I have the whole picture. Let me pitch a scenario: > > Existing system is single disk, no RAID > sda = Existing disk > sda1 = Small boot partition > sda2 = Large LVM PV > LVM volume group name VolGroup00 > One or more filesystems and/or swap spaces in LVM LVs > Goal: Migrate system to RAID 1 in-place > > # make a full backup of everything to offline media > # test the backup > # add new new disk as /dev/sdc > # set partitions on sdc to be same or larger than sda > # create degraded mirrors on new disk > mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdc1 missing > mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sdc2 missing > # initialize md1 as an LVM PV > pvcreate /dev/md1 > # add new the PV to the existing VG (Volume Group) > vgextend VolGroup00 /dev/md1 > # make sure that backup is still there > # move data to new PV > pvmove /dev/sda2 /dev/md1 > # get coffee, make sandwich, read book, etc. > # remove the now unused old PV from old disk > vgreduce VolGroup00 /dev/sda2 > # (things get vague now, 'cause I don't want to type everything) > # (if anyone wants help on something, say so) > # migrate boot partition to /dev/md0 > # zero first block of /dev/sda1 and /dev/sda2 to avoid confusion > # add sda partitions to mirror sets > mdadm --add /dev/md0 /dev/sda1 > mdadm --add /dev/md1 /dev/sda2 > # install boot loader on /dev/md0 and/or on /dev/sdc > # maybe some other stuff that I forgot > > In this case, I set up /dev/md0 with no problem and my system is booting with /dev/md0 as the /boot filesystem.
mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sdc2 missing The difference between the way I did it an your suggestion is I had missing before the /dev/sdc2. mdadm --create /dev/md1 --level=1 --raid-devices=2 missing /dev/sdc2 Was accomplished as was the 'dd if=/dev/zero of=/dev/md1 bs=512 count=1' I tried this with and witout a filesystem on /dev/md1. -- Jerry Feldman <g...@blu.org> Boston Linux and Unix PGP key id: 537C5846 PGP Key fingerprint: 3D1B 8377 A3C0 A5F2 ECBB CA3B 4607 4319 537C 5846
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