Hi Folks,
I'm writing you in the hopes that someone can give me some advise on
some big problems I'm having with a 1.8TB LV. If this is the wrong place
for this kind of question and you happen to know the right place to ask,
please direct me there.
First let me explain what has happened and my setup.
I have (had) 2 software raid 5 arrays generated with mdadm on a 2.6.22
based system. Each array contained 3 disks - though the sets were of
different sizes.
md0 (RAID 5):
/dev/sde1 (1TB)
/dev/sdf1 (1TB)
/dev/sdg1 (1TB)
md1 (RAID 5):
/dev/sda1 (750GB)
/dev/sdb1 (750GB)
/dev/sdc1 (750GB)
Initially I started out with a simple LVM called 'array' in the volume
group 'raid' sitting on md0. Over time this disk was populated to 90%
capacity.
So following the steps outlined on various how-to's through out the
internet I managed to extend the volume group 'raid' and then extend the
logical volume 'array' with the additional space. I then used resize2fs
to resize the file system (while it was offline of course).
I then remounted the file system successfully and it had grown to
roughly 3.1TB of usable space (great). After remounting I did a few
simple test writes to it and copied a few ISO images over to make sure
everything was working.
Well to my great luck I awoke this morning to find that md1 had
degraded. Last night the second disk in the set (/dev/sdb1) threw a few
sector errors (nothing critical - or so I thought). Examining
/proc/mdstat indicated that the entire md1 array had failed. Both
/dev/sdb1 and /dev/sdc1 were marked as failed and offline. This had me
worried but I wasn't too concerned as i had not yet written any critical
data to LVM (at least nothing I couldn't recover). So after messing
around with md1 for nearly 2 hours trying to figure out why both disks
fell out of the array (I have yet to determine why it booted /dev/sdc1
out - as there were no errors found on it, reported, etc). I decided
that I would try and reboot to see if some thread was hung, something
unexplained could be corrected by a restart. At this point things went
from problematic to down right horrible.
As soon as the system came back online md1 was still no where to be
found, md0 was there and still in tact. However because md1 was missing
from the volume group, the volume group could not start and thus the
logical volume was unavailable. After searching around I kept coming
back to suggestions stating that removal of the missing device from the
volume group was the solution to getting thing back online again. So
using 'vgreduce --removemissing raid' then 'lvchange -ay raid' to update
the changes - Neither command errored and vgreduce noted that 'raid' was
not available again.
So as it stands now I have no logical volume, I have a volume group and
I have a functional md0 array. If I dump the first 50 or so megs of the
md0 raid array I can see the volume group information, as well as the lv
information including various bits of file system information.
At this point I'm wondering can I recover the logical volume and recover
this 1.8TB of data.
For completeness here is the results of various display and scan commands:
root@Aria:/dev/disk/by-id# pvscan
PV /dev/md0 VG raid lvm2 [1.82 TB / 1.82 TB free]
Total: 1 [1.82 TB] / in use: 1 [1.82 TB] / in no VG: 0 [0 ]
root@Aria:/dev/disk/by-id# pvdisplay
--- Physical volume ---
PV Name /dev/md0
VG Name raid
PV Size 1.82 TB / not usable 2.25 MB
Allocatable yes
PE Size (KByte) 4096
Total PE 476933
Free PE 476933
Allocated PE 0
PV UUID oI1oXp-NOSk-BJn0-ncEN-HaZr-NwSn-P9De9b
root@Aria:/dev/disk/by-id# vgscan
Reading all physical volumes. This may take a while...
Found volume group "raid" using metadata type lvm2
root@Aria:/dev/disk/by-id# vgdisplay
--- Volume group ---
VG Name raid
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 11
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 1
Act PV 1
VG Size 1.82 TB
PE Size 4.00 MB
Total PE 476933
Alloc PE / Size 0 / 0
Free PE / Size 476933 / 1.82 TB
VG UUID quRohP-EcsI-iheW-lbU5-rBjO-TnqS-JbjmZA
root@Aria:/dev/disk/by-id# lvscan
root@Aria:/dev/disk/by-id#
root@Aria:/dev/disk/by-id# lvdisplay
root@Aria:/dev/disk/by-id#
Thank you.
-cf
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