A linux utility used to manage software RAID devices.

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lost superblock in md raid

Issue on Red Hat Linux 5. Due to some miscommunication two LUNs in our environment were enlarged from 1.2 TB to 1.7 TB. Now, after a reboot, mdadm does not find the superblocks to build the array ...
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2answers
8k views

How do I recover files from a single degraded mdadm raid1 drive? “not enough to start the array”

Given a single raid1 drive in degraded/rebuilding state, can it be force mounted? I'd like to recover all the files before undertaking the dangerous operation of pairing it and rebuilding. As far as ...
4
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2answers
7k views

Ubuntu: How do the md devices get assembled at bootup?

How do the md devices get assembled at bootup in Ubuntu? Is /etc/mdadm/mdadm.conf truly the relevant factor here? My mdadm.conf is sound and I checked that while I was in the rescue CD environment. ...
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0answers
454 views

Disable RAID auto detect at runtime

In Linux, I'm partitioning two disks for RAID1 with fdisk. The first disk partitioning succedes, but the second fail because the raid starts automatically and occupy also the second disk (why? it ...
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2answers
501 views

How does mdraid resync work?

I have two drives in a mirror (linux sw raid/mdadm); one drive somehow left the mirror in the past and its content is now several days old. At this moment, I'm using degraded mirror (with one drive ...
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2answers
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Unable to rename a RAID device: stuck with /dev/md126

I had a fully working server. I booted with SystemRescueCD, without writing anything. I didn't even mounted a partition. Then rebooted the server. The server no longer boot correctly because some ...
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3answers
6k views

Can I create a software RAID 1 with one device

I have a single disk that I want to create a Mirror of, Lets call this disk sda I have just bought another identicle size disk, which we can call sdb. sda and sdb have one partition called sda1 and ...
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1answer
505 views

How do I recover a broken software RAID5 array?

Ack, I think I screwed up bad. I had a power failure on a RAID5 array which caused the metadata to be inconsistent between drives. I followed the advice here except a case of fat fingers caused me to ...
2
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1answer
232 views

Can MD cope with a badblock list?

I have a MD drive set in RAID6 configuration with LVM2 on top. One of my drives was faulted last night due to bad blocks. Now apart from the fact that I am aware I should physically replace the drive, ...
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1answer
1k views

convert /dev/md0 to /dev/sda1

I used a Software-RAID I and want to access the data without RAID now. After mdadm --fail /dev/md0 /dev/sda1 mdadm --remove /dev/md0 /dev/sda1 I tried mount -t ext4 /dev/sda1 /mnt but dmesg ...
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1answer
990 views

Unable to mount raid on my NAS, trying to rescue the data, how should I proceed?

A short backstory: something happened on my Synology NAS, apparently a buggy mailserver program that came with an update stopped the device from seeing the 2x3TB drives I have. After a lot of ...
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1answer
575 views

Ubuntu Software Raid5 - /dev devices changed, will mdadm raid break

I had a major server failure. The OS is fine and back up and running. Before I plug my raid drives back in and try and mount it I need to ask this simple question. The drives that originally mapped ...
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1answer
451 views

Recover MDADM Raid 5 in LVM with badblocks

I'm pretty sure I'm dealing with at stuffed RAID 5 array. Two of the drives were listed as failed in /proc/mdstat and mdadmdetails: 0 0 8 33 0 active sync /dev/sdc1 ...
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3answers
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RAID5 recovery trying with “mdadm --create … missing”

First how I got in this situation: I had an RAID5 array with disks each 2TB (external USB-disks), I then wanted to create a larger encrypted array. Therefore I got 2 additional disks (also 2 TB each) ...
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2answers
4k views

/dev/md127 refuses to stop. No open files

So I'm trying to stop /dev/md127 on my Ubuntu 12.10 box. It was set up as RAID1, but I'm trying to move everything (well, rename) to md0. I read that renaming isn't possible, so I'm trying to remove ...
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0answers
54 views

Change numbers in the Number column to be consecutive from 0 for an mdadm RAID array

I have a RAID 1 array: # mdadm --detail /dev/md0 /dev/md0: Version : 1.2 Creation Time : Thu Oct 18 21:52:43 2012 Raid Level : raid1 Array Size : 1048564 (1024.16 MiB 1073.73 MB) ...
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1answer
9k views

Using UUID's with mdadm

I'm using GPT as my partitioning scheme. I check the UUID's of my partitions: # ls -l /dev/disk/by-partuuid/ total 0 lrwxrwxrwx 1 root root 10 Oct 18 22:39 0793009a-d460-4f3d-83f6-8103f8ba24e2 -> ...
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1answer
573 views

TrueCrypt is destoying mdadm volume

I'm setting up a new file server using the same storage configuration as my existing server, but the procedure is failing and i cannot figure out why. my goal is to create a TrueCrypt volume on top ...
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2answers
8k views

What's the difference between mdadm state “active” and state “clean”

I have two different computers with different RAID5 arrays. When I run the command mdadm --detail /dev/md0 one drive reports "active" while the other reports "clean" for the "state" field. What ...
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1answer
246 views

Issue with degraded raid5 after power outage

I have a raid5 that consists of 8 disks. After a power outage mdadm tells me that the raid is degraded. Here is the output: /dev/md0: Version : 0.90 Creation Time : Sat Jul 10 09:08:28 2010 ...
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2answers
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What keeps one side of an rsync so busy?

I've got a Debian machine on my LAN serving as a backup server for the others. It has four HDDs combined into a software RAID 5 md device, on that an LVM, and on that btrfs. Backups are made using ...
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1answer
2k views

RAID 10 can not be started

I have a RAID 10 array managed with mdadm which has failed . The symptom was that X has crashed and I was unable to logon from the terminal. I have restarted the computer and /dev/md1 did not start. ...
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2answers
4k views

Grow/resize RAID when upgrading visible size of disks

I originally created a software RAID using a controller that could only address 2TB per disk. The disks are 3 TB disks. It worked fine, but only used the first 2TB of each disk. I have now changed ...
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3answers
722 views

Recovery of data on raid5+lvm reiserfs partition, after raid5 problems

I've got a server with 3 sata hard drives. Each has 2 partitions: one small is part of /dev/md0, a raid1 array (/boot), rest is part of a raid5 array (/dev/md1), which is an lvm physical volume. ...
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338 views

Software raid checksumming slow

On my new 24 disk array I get 900 MB/s of raw read or write using dd to all the disks. When I set the disks up as a 24 disk RAID6 I get 400 MB/s write and 600 MB/s read. It seems to be due to ...
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1answer
71 views

Is S25mdadm start script priority correct?

(On Ubuntu 11.10 - configuration inherited from 10.10) Occasionally the boot process seems to suffer a race condition where a starting process misses some of the Raid-1 FSes, build via mdadm. ...
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3answers
46k views

How to check mdadm raids while running?

I'm starting to get a collection of computers at home and to support them I have my "server" linux box running a raid array. Its currently mdadm raid1, going to raid5 once I have more drives (and ...
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2answers
10k views

MDADM - how to reassemble RAID-5 (reporting device or resource busy)

I rather new to the linux scene, and don't have nearly enough experience to actually consider myself somebody that can be trusted with using the system :P Anyhow long story short - I decided to use ...
6
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3answers
7k views

Using mdam --examine to write mdadm.conf

I'm trying to script the RAID setup for a (growing) number of identical servers. The advice I've seen for using mdadm suggests that once the RAID array has been created you can run mdadm --examine ...
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3answers
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Grub2 RAID /boot

I'm using Gentoo on my HomeServer. My HDDs are raid1 mirrored with mdadm. My problem is how to boot the /boot partition correct? /dev/md1 consists of /dev/sdc2 & /dev/sdd2 mounted on /boot In ...
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6answers
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Pros and cons of software Parity-RAID (e.g. RAID5)

I was recently told about some problems concerning Parity-RAIDs without a non-volatile cache. More exspensive HW-controllers do have battery-powered caches to finish write-operations in case of power ...
7
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1answer
12k views

mdadm raid1 and what chunksize (or blocksize) on 4k drives?

I want to use two 3 TB drives in a mdadm raid1 setup (using Debian Sequeeze). The drives use 4k hardware sectors instead of the traditional 512 byte ones. I am a bit confused because on the one hand ...
7
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1answer
3k views

mdadm Raid5 gives spares missing events

I succesfully builded up a raid5 array on debian testing (Wheezy). As the manpages and further tell, the array would be created as an out of sync array with just a new spare injected to be repaired. ...
9
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1answer
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grub error “superfluous RAID member” on update-grub

My system (wheezy/sid: 2.6.32-5-amd64 #1 SMP x86_64 GNU/Linux) is running fine - I'm just wondering what some messages mean. I have two mdraid arrays running up on my system. Here's cat /proc/mdstat: ...
6
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2answers
2k views

Will the system make sure that mdadm is sync-ed before completing a reboot?

This is a follow up to my crazy mdadm problem. I'm trying to figure out what might have caused sda to get out of sync in the first place. The only thing I can think of is that I had just run a bunch ...
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1answer
1k views

installing grub 2 on mdadm, which device?

when installing grub(2) to mdadm devices are you supposed to install it to /dev/sdX or /dev/mdX?
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1answer
379 views

Drive was unable to assemble into the array

I ran mdadm -A /dev/md0 /dev/sda1 /dev/sdb1 Only /dev/sdb1 was loaded into the array though. I have a few more arrays on the same two drives too. Each time the partition on sda failed. dmesg told ...
4
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2answers
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what is commit=0 for ext4? does mdadm not support it?

I see this in my dmesg log EXT4-fs (md1): re-mounted. Opts: commit=0 EXT4-fs (md2): re-mounted. Opts: commit=0 EXT4-fs (md3): re-mounted. Opts: commit=0 I think that means that dealloc is disabled? ...