How to fix mistake on raid: mdadm create instead of assemble?
Hi guys,
I'm new to RAID although I've had a server running raid5 for a while. It was delivered preinstalled like this and I never really wondered how to monitor and maintain it. This quick introduction just to let you understand why I'm such an idiot asking such a silly question.
Now what happened?
I have a server with 4 disks and raid5 configured. /dev/md10 is made of sda10, sdb10, sdc10 and sdd10.
Unfortunately, /dev/sdd died, the server crashed, etc. After restart, md10 did not rebuilt. I understood sdd was dead and did not try to force rebuild or even touch the existing system.
First thing I did is ddrescue the remaining partitions sd[abc]10. ddrescue did not stumble into any read error so I assume all remaining partitions are perfectly safe.
Then I examined the partitions with :
Code:
# mdadm --examine /dev/loop[012]
/dev/loop0:
Magic : a92b4efc
Version : 0.90.00
UUID : 9d37bc89:711887ae:a4d2adc2:26fd5302
Creation Time : Wed Jan 25 09:08:11 2012
Raid Level : raid5
Used Dev Size : 1926247296 (1837.01 GiB 1972.48 GB)
Array Size : 5778741888 (5511.04 GiB 5917.43 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 10
Update Time : Mon Sep 5 23:29:23 2016
State : clean
Active Devices : 3
Working Devices : 3
Failed Devices : 1
Spare Devices : 0
Checksum : 9d0ce26d - correct
Events : 81589
Layout : left-symmetric
Chunk Size : 64K
Number Major Minor RaidDevice State
this 0 8 10 0 active sync
0 0 8 10 0 active sync
1 1 8 26 1 active sync
2 2 8 42 2 active sync
3 3 0 0 3 faulty removed
/dev/loop1:
Magic : a92b4efc
Version : 0.90.00
UUID : 9d37bc89:711887ae:a4d2adc2:26fd5302
Creation Time : Wed Jan 25 09:08:11 2012
Raid Level : raid5
Used Dev Size : 1926247296 (1837.01 GiB 1972.48 GB)
Array Size : 5778741888 (5511.04 GiB 5917.43 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 10
Update Time : Mon Sep 5 23:36:23 2016
State : clean
Active Devices : 1
Working Devices : 1
Failed Devices : 2
Spare Devices : 0
Checksum : 9d0ce487 - correct
Events : 81626
Layout : left-symmetric
Chunk Size : 64K
Number Major Minor RaidDevice State
this 1 8 26 1 active sync
0 0 0 0 0 removed
1 1 8 26 1 active sync
2 2 0 0 2 faulty removed
3 3 0 0 3 faulty removed
/dev/loop2:
Magic : a92b4efc
Version : 0.90.00
UUID : 9d37bc89:711887ae:a4d2adc2:26fd5302
Creation Time : Wed Jan 25 09:08:11 2012
Raid Level : raid5
Used Dev Size : 1926247296 (1837.01 GiB 1972.48 GB)
Array Size : 5778741888 (5511.04 GiB 5917.43 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 10
Update Time : Mon Sep 5 23:29:23 2016
State : clean
Active Devices : 3
Working Devices : 3
Failed Devices : 1
Spare Devices : 0
Checksum : 9d0ce291 - correct
Events : 81589
Layout : left-symmetric
Chunk Size : 64K
Number Major Minor RaidDevice State
this 2 8 42 2 active sync
0 0 8 10 0 active sync
1 1 8 26 1 active sync
2 2 8 42 2 active sync
3 3 0 0 3 faulty removed
There comes my mistake: I ran the --create command instead of --assemble:
Code:
# mdadm --create --verbose /dev/md1 --raid-devices=4 --level=raid5 --run --readonly /dev/loop0 /dev/loop1 /dev/loop2 missing
mdadm: layout defaults to left-symmetric
mdadm: layout defaults to left-symmetric
mdadm: chunk size defaults to 512K
mdadm: /dev/loop0 appears to contain an ext2fs file system
size=5778741888K mtime=Sat Sep 3 11:00:22 2016
mdadm: /dev/loop0 appears to be part of a raid array:
level=raid5 devices=4 ctime=Wed Jan 25 09:08:11 2012
mdadm: /dev/loop1 appears to be part of a raid array:
level=raid5 devices=4 ctime=Wed Jan 25 09:08:11 2012
mdadm: /dev/loop2 appears to be part of a raid array:
level=raid5 devices=4 ctime=Wed Jan 25 09:08:11 2012
mdadm: size set to 1926115840K
mdadm: automatically enabling write-intent bitmap on large array
mdadm: creation continuing despite oddities due to --run
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md1 started.
After that, mounting failed:
Code:
# mount /dev/md1 /raid/
mount: /dev/md1 is write-protected, mounting read-only
mount: wrong fs type, bad option, bad superblock on /dev/md1,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so.
Here's more info about the new raid to be compared with the initial one:
Code:
# mdadm --examine /dev/loop[012]
/dev/loop0:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x1
Array UUID : aa56f42f:bb95fbde:11ce620e:878b2b1c
Name : tucana.caoba.fr:1 (local to host tucana.caoba.fr)
Creation Time : Mon Sep 19 23:17:04 2016
Raid Level : raid5
Raid Devices : 4
Avail Dev Size : 3852232703 (1836.89 GiB 1972.34 GB)
Array Size : 5778347520 (5510.66 GiB 5917.03 GB)
Used Dev Size : 3852231680 (1836.89 GiB 1972.34 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Unused Space : before=262056 sectors, after=1023 sectors
State : clean
Device UUID : b4622e59:f0735f5a:825086d1:57f89efb
Internal Bitmap : 8 sectors from superblock
Update Time : Mon Sep 19 23:17:04 2016
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : 3ec8dda7 - correct
Events : 0
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 0
Array State : AAA. ('A' == active, '.' == missing, 'R' == replacing)
/dev/loop1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x1
Array UUID : aa56f42f:bb95fbde:11ce620e:878b2b1c
Name : tucana.caoba.fr:1 (local to host tucana.caoba.fr)
Creation Time : Mon Sep 19 23:17:04 2016
Raid Level : raid5
Raid Devices : 4
Avail Dev Size : 3852232703 (1836.89 GiB 1972.34 GB)
Array Size : 5778347520 (5510.66 GiB 5917.03 GB)
Used Dev Size : 3852231680 (1836.89 GiB 1972.34 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Unused Space : before=262056 sectors, after=1023 sectors
State : clean
Device UUID : 9d42153b:4173aeea:51f41ebc:3789f98a
Internal Bitmap : 8 sectors from superblock
Update Time : Mon Sep 19 23:17:04 2016
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : 2af1f191 - correct
Events : 0
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 1
Array State : AAA. ('A' == active, '.' == missing, 'R' == replacing)
/dev/loop2:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x1
Array UUID : aa56f42f:bb95fbde:11ce620e:878b2b1c
Name : tucana.caoba.fr:1 (local to host tucana.caoba.fr)
Creation Time : Mon Sep 19 23:17:04 2016
Raid Level : raid5
Raid Devices : 4
Avail Dev Size : 3852232703 (1836.89 GiB 1972.34 GB)
Array Size : 5778347520 (5510.66 GiB 5917.03 GB)
Used Dev Size : 3852231680 (1836.89 GiB 1972.34 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Unused Space : before=262056 sectors, after=1023 sectors
State : clean
Device UUID : ada52b0e:f2c4a680:ece59800:6425a9b2
Internal Bitmap : 8 sectors from superblock
Update Time : Mon Sep 19 23:17:04 2016
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : 2a341a - correct
Events : 0
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 2
Array State : AAA. ('A' == active, '.' == missing, 'R' == replacing)
With the help of the initial mdadm --examine, is it possible to recreate my raid in a way that I can read data out of it?
Hello,
i have a system with 6 sata3 seagate st3000dm01 disks running on stable Debian with software raid mdadm. i have md0 for root and md1 for swap and md2 for the files. i now want to add one more disk = sdh4 for md2 but i got this errors:
The new disk is connected to an 4 port sata... (7 Replies)
Hello,
I want to delete a RAID configuration an old server has.
Since i haven't the chance to work with the specific raid controller in the past can you please help me how to perform the configuraiton?
I downloaded IBM ServeRAID Support CD but i wasn't able to configure the video card so i... (0 Replies)
Hi All,
I have been trying to create a USB RAID 5 using mdadm tool on Joli OS 1.2 (Ubuntu) but with no luck. I cannot even get pass the creation of array device (/dev/md0) and superblock. I am using 3 USB keys (2 16.4 GB kingston and 1 16GB sandisk).
My steps are:
... (5 Replies)
had this RHEL 5 installation with /dev/sda1 and /dev/sda2 running..
created two more partitions /dev/sdj1 and /dev/sdj2 , the same sized partition as /dev/sda
trying to use mdadm to create RAID1 ..
I cannot even do it in "rescue" mode, I wonder if it can be done..
it kept... (2 Replies)
Hello, I have 4 drives (500G each) in a raid 10, I got a power failior and this is the result?
cat /proc/mdstat
Personalities :
md126 : inactive sdb sdc sdd sde
1953536528 blocks super external:-md127/0
md127 : inactive sdd(S) sde(S) sdb(S) sdc(S)
9028 blocks super... (3 Replies)
Hello,
I have a scsi pci x raid controller card on which I had created a disk array of 3 disks
when I type lspv ; I used to see 3 physical disks ( two local disks and one raid 5 disk )
suddenly the raid 5 disk array disappeared ; so the hardware engineer thought the problem was with SCSI... (0 Replies)
Hi guys,
i must install an old old old ml370 server...
I must create a RAID 5 with my 4 SCSI disk.
I need a SmartStart disk for create it or a Floppy Disk called "Array configuration Tool". I don't find it on the hp website...:mad::mad::mad:
Anyone have it??
Thanks in advance.
Zio (0 Replies)
Hi,
I flashed one SunFire V120 (flarcreate) and dump the flar on to a SunFire V880. It goes smooth until the first reboot.
SunOS Release 5.8 Version Generic_108528-22 64-bit
Copyright 1983-2003 Sun Microsystems, Inc. All rights reserved.
Cannot assemble drivers for root... (8 Replies)
Hi, there are tons of RAID1 tutorials, but none of them deal with lvm. The problem is that I want to expand my current lvm partition over RAID1 rather than creating a new lvm partition after RAID1 is created.
My master harddrive has lvm partition. I'm wondering how to create a RAID1 image of... (1 Reply)
