linux raid-10 far=2 "filesystem damaged" false alarm?
Posted: 16 May 2012, 08:29
I hit a (seemingly) disk related hiccup, and while everything seemed fine after a reboot,
I tried out all the checking tools I could. TestDisk gave a report that concerned me,
but I now suspect it might be a false positive due to my configuration.
I'll like to check that interpretation with the experts.
So I have two disk set up in RAID-10, which usually makes no sense, but under
linux with "far" or "near" parameters, can be useful.
/dev/sda2 and /dev/sdb2 are raided with far=2
testdisk on /dev/sda2 reports what I expect
testdisk on /dev/sdb2 doesn't find a filesystem (see below)
I now think that the inverted block organization on /dev/sdb2 caused
by the far=2 parameter may just be making it look less like a filesystem
and so is causing a false alarm. Could that be the case?
The smart tools and mdadm checks seem to be saying everything is fine,
but gparted (not lvm aware?) give a similar "no partition" warning.
(If it's already not clear, I should say I don't have a clue about this stuff
and am staggering around in the dark)
Is there any other info that would be useful?
Thanks
I tried out all the checking tools I could. TestDisk gave a report that concerned me,
but I now suspect it might be a false positive due to my configuration.
I'll like to check that interpretation with the experts.
So I have two disk set up in RAID-10, which usually makes no sense, but under
linux with "far" or "near" parameters, can be useful.
/dev/sda2 and /dev/sdb2 are raided with far=2
testdisk on /dev/sda2 reports what I expect
testdisk on /dev/sdb2 doesn't find a filesystem (see below)
I now think that the inverted block organization on /dev/sdb2 caused
by the far=2 parameter may just be making it look less like a filesystem
and so is causing a false alarm. Could that be the case?
The smart tools and mdadm checks seem to be saying everything is fine,
but gparted (not lvm aware?) give a similar "no partition" warning.
(If it's already not clear, I should say I don't have a clue about this stuff
and am staggering around in the dark)
Code: Select all
# mdadm --examine /dev/sda2 /dev/sdb2 | egrep '^/dev|raid|Layout|State'
/dev/sda2:
Raid Level : raid10
State : clean
Layout : near=1, far=2
Number Major Minor RaidDevice State
/dev/sdb2:
Raid Level : raid10
State : clean
Layout : near=1, far=2
Number Major Minor RaidDevice State
==> dev-sda <==
Disk /dev/sda - 251 GB / 233 GiB - CHS 30522 255 63
Partition Start End Size in sectors
D Linux 0 1 1 13 254 63 224847
D Linux RAID 0 1 1 13 254 63 224847 [md0]
D Linux LVM 14 0 1 30521 254 63 490111020
D Linux RAID 14 14 15 30521 254 63 490110124 [md1]
==> dev-sdb <==
Disk /dev/sdb - 251 GB / 233 GiB - CHS 30522 255 63
Partition Start End Size in sectors
D Linux 0 1 1 13 254 63 224847
D Linux RAID 0 1 1 13 254 63 224847 [md0]
* Linux 6246 0 1 11381 254 63 82509840
No file found, filesystem seems damaged.
Post "Deep Analyse":
Disk /dev/sdb - 251 GB / 233 GiB - CHS 30522 255 63
Partition Start End Size in sectors
D Linux 0 1 1 13 254 63 224847
D Linux RAID 0 1 1 13 254 63 224847 [md0]
D Linux 6246 0 1 11381 254 63 82509840
D Linux 8182 0 1 9160 254 63 15727635
Thanks
