Hi,
For the third time, I had to change a failed drive from my home linux RAID5
box. Previous time went right and this time, I don't know what I did wrong,
but I broke my RAID5. Well, at least, he won't start.
/dev/sdb was the failed drive
/dev/sdc and /dev/sdd are OK.
I tried to reassamble the RAID with this command after I replace sdb and
create a new partition :
~# mdadm -Cv /dev/md0 --assume-clean --level=5
--raid-devices=3 /dev/sdc1 /dev/sdd1 /dev/sdb1
Well, I gues I did a mistake here, I should have done this instead :
~# mdadm -Cv /dev/md0 --assume-clean --level=5
--raid-devices=3 /dev/sdc1 /dev/sdd1 missing
Maybe this wipe out my data...
Let's go futher, then, pvdisplay, pvscan, vgdisplay returns empty
information :-(
Google helped me, and I did this :
~# dd if=/dev/md0 bs=512 count=255 skip=1 of=/tmp/md0.txt
[..]
physical_volumes {
pv0 {
id = "5DZit9-6o5V-a1vu-1D1q-fnc0-syEj-kVwAnW"
device = "/dev/md0"
status = ["ALLOCATABLE"]
flags = []
dev_size = 7814047360
pe_start = 384
pe_count = 953863
}
}
logical_volumes {
lvdata {
id = "JiwAjc-qkvI-58Ru-RO8n-r63Z-ll3E-SJazO7"
status = ["READ", "WRITE", "VISIBLE"]
flags = []
segment_count = 1
[..]
Since I saw lvm information, I guess I haven't lost all information yet...
I tried an unhoped command :
~# pvcreate --uuid "5DZit9-6o5V-a1vu-1D1q-fnc0-syEj-kVwAnW" --restorefile /etc/lvm/archive/lvm-raid_00302.vg /dev/md0
Then,
~# vgcfgrestore lvm-raid
~# lvs -a -o +devices
LV VG Attr LSize Origin Snap% Move Log Copy% Convert Devices
lvdata lvm-raid -wi-a- 450,00g /dev/md0(148480)
lvmp lvm-raid -wi-a- 80,00g /dev/md0(263680)
Then :
~# lvchange -ay /dev/lvm-raid/lv*
I was quite happy until now.
Problem appears now when I try to mount those 2 LV (lvdata & lvmp) as ext4 partition :
~# mount /home/foo/RAID_mp/
~# mount | grep -i mp
/dev/mapper/lvm--raid-lvmp on /home/foo/RAID_mp type ext4 (rw)
~# df -h /home/foo/RAID_mp
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/lvm--raid-lvmp 79G 61G 19G 77% /home/foo/RAID_mp
Here is the big problem
~# ls -la /home/foo/RAID_mp
total 0
Worst on the other LVM :
~# mount /home/foo/RAID_data
mount: wrong fs type, bad option, bad superblock on /dev/mapper/lvm--raid-lvdata,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so
I bet I recover the LVM structure but the data are wiped out, don't you think ?
~# fsck -n -v /dev/mapper/lvm--raid-lvdata
fsck from util-linux-ng 2.17.2
e2fsck 1.41.11 (14-Mar-2010)
fsck.ext4: Group descriptors look bad... trying backup blocks...
fsck.ext4: Bad magic number in super-block when using the backup blocks
fsck.ext4: going back to original superblock
fsck.ext4: Device or resource busy while trying to open /dev/mapper/lvm--raid-lvdata
Filesystem mounted or opened exclusively by another program?
Any help is welcome if you have any idea how to rescue me pleassse !
--
LMJ
"May the source be with you my young padawan"
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