A linux utility used to manage software RAID devices.
Questions tagged [mdadm]
864 questions
6
votes
4 answers
How to recover raid? mount: can't read superblock
I had a raid5 array on /dev/md0 created with mdadm and it was working fine for about a year. It consisted of three HDDs of 1TB each. A few days ago there was a power failure and UPS failure. It was not the first time unfortunately.
The OS is on a…
kapcom01
- 231
4
votes
1 answer
How to get rid of a stubborn 'removed' device in mdadm
One of my server's drives failed and so I removed the failed drive from all three relevant arrays, had the drive swapped out, and then added the new drive to the arrays. Two of the arrays worked perfectly. The third added the drive back as a spare,…
T.J. Crowder
- 887
3
votes
0 answers
Why mdadm --examine --scan gives two same ARRAYs?
The following confuses me:
[root@mrak ~]# mdadm --examine --scan
ARRAY /dev/md/0 metadata=1.2 UUID=d3f800db:26de8691:dc0caf45:0f75028b name=mrak.dex.internal:0
ARRAY /dev/md/0 metadata=1.2 UUID=1870fd84:2234e3d4:580f7634:b0b621e7…
DejanLekic
- 304
2
votes
1 answer
what is the purpose of mdadm's check command?
I discovered one of my servers running slower than usual today because of the checkarray launched by a cronjob installed by default on the server. This is Ubuntu 14.
In this particular case, I have just a single RAID1.
What is the purpose of this…
Matías
- 447
2
votes
1 answer
how can I set the data offset on an mdadm device?
I am trying to recover from a degraded RAID array. I stupidly used mdadm --create somewhere along the way, and now a couple of my devices have incorrect superblocks. Luckily I kept a copy of the old superblocks:
/dev/sdd1:
Magic :…
Kkkev
- 143
2
votes
1 answer
mdadm keeps removing disk
As the title suggests, mdadm keeps marking a drive as "Removed" (from mdadm --detail) and I was hoping to get suggestions as to why that might happen.
I was wanting to fsck the drives however I got the following error:
$ fsck /dev/sda1
fsck from…
kierans
- 133
2
votes
2 answers
mdadm resync causes system to become unresponsive
We have a server on which a raid 1 disk is trying to rebuild or sync. The disk is resyncing but the server has become unresponsive. One cannot ssh into the box nor are any of the services responding. If you are on the local lan you can ssh in but it…
mxc
- 151
1
vote
1 answer
mdadm RAID configuration changes disk sdXX naming randomly on reboot
I have an issue with software raid i build over 2 expanders with disks loaded as JBOD. After every reboot of server, the naming of virtual drives changes and also the array numbers and logic are scattered. example:
NAME MAJ:MIN RM SIZE RO…
J B
- 93
1
vote
0 answers
mdadm does not let me set --size manually, but grows to the same size later
I'm trying to make raid1 out of 2 disks the size of which differs a lot (ec2 provides iops based on disk size, so I want to have more iops, but don't care about losing some free space).
However when I set the size manually, I get is smaller than…
Fluffy
- 171
1
vote
2 answers
Increase space on RAID 10
I have a RAID10 with 7 working devices ,4 actives and 3 spares .I want to increase the RAID's space from 4 devices to 6 .
i use this :
sudo mdadm --grow --raid-devices=6 /dev/md0
but it gives me this message :
mdadm :insufficient head-space for…
Asis
- 21
1
vote
1 answer
mdadm update time and resync
I detached one half of my linux md raid1 (--fail --remove) to do some potentially risky filesystem work, to be sure I had a good copy on hand if things went bad. Things went well, and now I want to resync the now out of date half.
Can I just --add…
user1238763
- 21
1
vote
2 answers
Linux: very slow mdadm resync on raid 1
I'm trying to rsync a RAID 1 on a system with absolutely nothing running ( i've moved all services to another server ). So it's just me via ssh. For some reason, it's very slow:
cat /proc/mdstat
Personalities : [raid1]
md1 : active raid1 sdc1[1]…
Fernando
- 1,229
1
vote
2 answers
Change Chunk Size On Existing Software raid 0 Array
Is it possible to change the chunk size on an existing software raid 0 array?
Operating system: Ubuntu 10.04 64bit
Mdadm Version: Version : 2.6.7.1
Kernel:2.6.32-33
Stephen
- 201
0
votes
0 answers
Force mdadm to stop array if a disk failure is detected
Is it possible to have mdadm automatically stop the array if any disk-failure is detected to limit data corruption?
Or better yet: Could it change the array to read-only? If so, would Linux handle it ok if one of its disks all-of-a-sudden went…
Markus A.
- 419
0
votes
1 answer
Ubuntu raid - can't boot - mdadm
I was trying to copy the /tmp to another disk (Ubuntu 14.04 server), however after doing so, any command that I typed to the shell started to throw errors.
I tried to reboot it, but now it just hangs up and loops:
mdadm: create user root not…
