Thread: Trouble rebuilding Raid1 array

hello everyone, registered while ago, can't i've been active member far

hope able me out here though:
built new computer, installed ubuntu 11.10, , got little problem when tried move on raid1 array consisting of 2 2tb disks (ext4) computer.

installed mdadm alright, silly me used mdadm --create create new array instead of mdadm --assemble (which assume would've worked perfectly?). anyway, created new raid1 array, got started, there's no filesystem on array.

tried mdadm --stop , mdadm --remove delete new array, tried building new array consisting of 1 disk + 1 missing, , adding second disk. got array started, there's no filesystem on array.

tried deleting new array again, deleting superblocks mdadm --zero-superblock on both disks. got little scared, ran disk check , yes both disks intact, there's identical ext4 filesystem on both of them , data there (phew!).

ok, i've got 2 identical disks, both ext4 , filled exact same data. figured there shouldn't problem creating brand new raid1 array now:
tried again creating new array,

code:

sudo mdadm --create /dev/md0 --verbose --level=1 --raid-devices=2 /dev/sdb1 /dev/sdc1

.
mdadm instantly started syncing 2 devices, seems went ok, , array running. it's running /dev/md127 reason? /dev/md0 doesn't exist, though in /etc/mdadm/mdadm.conf says clearly:

code:

# definitions of existing md arrays  array /dev/md0 uuid=8bb0d80b:d5fe4508:2db7a00c:528770c9

why chooses intrigues me, here's problem:

trying mount array gives me:

code:

wrong fs type, bad option, bad superblock on /dev/md127,         missing codepage or helper program, or other error         in cases useful info found in syslog - try         dmesg | tail  or so

dmesg | tail gives me

code:

dmesg | tail  [    5.325318] bluetooth: bnep filters: protocol multicast  [    5.393102] init: plymouth-stop pre-start process (1665) terminated status 1  [    6.902738] e1000e: eth0 nic link 1000 mbps full duplex, flow control: rx/tx  [    6.903058] addrconf(netdev_change): eth0: link becomes ready  [   17.439615] eth0: no ipv6 routers present  [  119.008404] ext4-fs (md127): vfs: can't find ext4 filesystem  [ 1632.922316] ext3-fs (md127): error: can't find ext3 filesystem on dev md127.  [ 1632.946159] ext2-fs (md127): error: can't find ext2 filesystem on dev md127.  [ 1632.994094] ext4-fs (md127): vfs: can't find ext4 filesystem  [ 1639.039044] ext4-fs (md127): vfs: can't find ext4 filesystem

any ideas anyone?

good news, got fixed. time consuming, quite easy solution actually, in case ever gets in same mess i'll write down did here:

1. did mdadm --zero-superblock on both disks, did disk check on them both mount them again. made new array 1 disk

code:

sudo mdadm --create /dev/md0 --verbose --level=1 --raid-devices=2 missing /dev/sdc1

2. made new ext4 fs on raid1 array mkfs.ext4.
3. mounted new array
4. copied files sdb1 array (with grsync)
5. added sdb1 array --add command

after done matter of waiting array resync, yet again. however, while previous resyncs went @ >100mb/s going @ ~4mb/s. solution found here: http://www.ducea.com/2006/06/25/incr...econstruction/ (note: had sudo -s -h in order permission change speed_limit_min).

now, done , everything's working it's supposed (for ).

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