Re: Corrupted ext4 filesystem after mdadm manipulation error

["L.M.J" <linuxmasterjedi@free.fr>]

Le Fri, 25 Apr 2014 09:36:12 -0400,
"Scott D'Vileskis" <sdvileskis@gmail.com> a écrit :

> As a last ditch effort, try the --create again but with the two
> potentially good disks in the right order:
> 
> mdadm --create /dev/md0 --level=5 --raid-devices=3 missing /dev/sdc1 /dev/sdd1


root@gateway:~# mdadm --create /dev/md0 --level=5 --raid-devices=3 missing /dev/sdc1 /dev/sdd1
mdadm: /dev/sdc1 appears to be part of a raid array:
    level=raid5 devices=3 ctime=Fri Apr 25 16:20:32 2014
mdadm: /dev/sdd1 appears to be part of a raid array:
    level=raid5 devices=3 ctime=Fri Apr 25 16:20:32 2014
Continue creating array? y
mdadm: array /dev/md0 started.


root@gateway:~# ls -l /dev/md*
brw-rw---- 1 root disk   9, 0 2014-04-25 16:34 /dev/md0
brw-rw---- 1 root disk 254, 0 2014-04-25 16:19 /dev/md_d0
lrwxrwxrwx 1 root root      7 2014-04-25 16:04 /dev/md_d0p1 -> md/d0p1
lrwxrwxrwx 1 root root      7 2014-04-25 16:04 /dev/md_d0p2 -> md/d0p2
lrwxrwxrwx 1 root root      7 2014-04-25 16:04 /dev/md_d0p3 -> md/d0p3
lrwxrwxrwx 1 root root      7 2014-04-25 16:04 /dev/md_d0p4 -> md/d0p4

/dev/md:
total 0
brw------- 1 root root 254, 0 2014-04-25 16:04 d0
brw------- 1 root root 254, 1 2014-04-25 16:04 d0p1
brw------- 1 root root 254, 2 2014-04-25 16:04 d0p2
brw------- 1 root root 254, 3 2014-04-25 16:04 d0p3
brw------- 1 root root 254, 4 2014-04-25 16:04 d0p4


root@gateway:~# cat /proc/mdstat 
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md0 : active raid5 sdd1[2] sdc1[1]
      3907023872 blocks level 5, 64k chunk, algorithm 2 [3/2] [_UU]
      
unused devices: <none>


root@gateway:~# pvscan 
  No matching physical volumes found


root@gateway:~# pvdisplay 



root@gateway:~# dd if=/dev/md0 of=/tmp/md0.dd count=10 bs=1M
10+0 enregistrements lus
10+0 enregistrements écrits
10485760 octets (10 MB) copiés, 0,271947 s, 38,6 MB/s


I can see in /tmp/md0.dd a lot of binary stuff, and sometimes, text :

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

segment1 {
start_extent = 0
extent_count = 115200

type = "striped"
stripe_count = 1        # linear

stripes = [

[...]

lvdata_snapshot_J5 {
id = "Mcvgul-Qo2L-1sPB-LvtI-KuME-fiiM-6DXeph"
status = ["READ"]
flags = []
segment_count = 1

segment1 {
start_extent = 0
extent_count = 25600

type = "striped"
stripe_count = 1        # linear

stripes = [
"pv0", 284160
]
}
}


[...]

lvdata_snapshot_J5 is a snap I've created a few days before my mdadm chaos, so i'm pretty sure some datas are
still on the drives... Am I wrong ?

Thanks




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