A linux utility used to manage software RAID devices.

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Expanding raid5 software raid

I have recently bought 4 2TB drives to expand my existing 4*2TB raid5 setup, using mdadm software raid in debian. As a initial step, I have created a raid5 on the four new drives and created an ...
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515 views

mdadm: Which disk is being rebuilt?

I noticed my software RAID1 degraded, and wanted to figure out which of the two disks in the array is being rebuilt/re-synced since they both show as being up. I am hoping someone can shed some light ...
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717 views

mdadm - raid device name changed on reboot

I'm not sure why, but after I restarted my ec2 instance, /dev/md0 didn't start as it normally would. after I saw what's available in /dev/md*, instead of seeing /dev/md0, there is a device there named ...
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87 views

MDADM did not kick off rebuild after a disk is inserted

I am new to Linux software RAID. I constructed a RAID6 with 6 hot-swappable SATA disks. I tested the failure scenario by unplugging 1 disk. The OS removed the devices from /dev and mdadm showed that ...
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202 views

removing software raid without data loss

i wonder if/how i can stop my linux machine using the installed software raid, without loosing any data. All information i found was about removing the superblock of any hdd, and this is o/c what i ...
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207 views

MDADM not assembling raid0 that is part of a raid5 on boot

I use a RAID0 (md2) as a device in a RAID5 (md3) setup (see below). Now everytime the computer boots, mdadm will mark md3 as degraded and i am forced to re-add md2 as a new spare. Of course mdadm then ...
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1k views

Removing raid metadata from drives

Normally when I have a drive which contains raid metadata e.g. from fakeraid or a hardware raid card I can get rid of it with: dmraid -r -E /dev/sdX Or if that doesnt work, doing a simple dd ...
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mdadm raid 1 grub only on sda

I just finished setting up a CentOS 6.3 64bit server with mdadm however a lightbulb went on and I realised grub would only be installed on the first drive which is about as much use and an ashtray on ...
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493 views

Why mdadm --examine --scan gives two same ARRAYs? [closed]

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 ...
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DegradedArray event on /dev/md1

This morning I got this message: This is an automatically generated mail message from mdadm running on A DegradedArray event had been detected on md device /dev/md1. Faithfully yours, etc. P.S. ...
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372 views

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 ...
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428 views

df showing wrong disk usage - disk corrupted

I'm getting a rather odd result from df from one of my disks using mdadm. It's setup as 4 of 2TB disks in raid 10. # df Filesystem Size Used Avail Use% Mounted on /dev/md2 ...
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230 views

Linux mdadm RAID5 data recovery with one drive failed, one drive failing

Improbably I had two drives fail in the same Raid5 array within 2 weeks of one another. Which means the array is dead. Yes yes hot spares not being lazy about replacing the failed drive I know. But ...
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322 views

mdadm did not notice a failed disk in raid0

I have a server with mdadm raid0: # mdadm --version mdadm - v3.1.4 - 31st August 2010 # uname -a Linux orkan 2.6.32-5-amd64 #1 SMP Sun Sep 23 10:07:46 UTC 2012 x86_64 GNU/Linux One of the disk has ...
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195 views

raid 5 mdadm drive dropped whilst growing

I have a 4x 2tb raid 5 mdadm array which I had begun to grow onto a 5th disk. ~# mdadm --add /dev/md1 /dev/sdb ~# mdadm --grow /dev/md1 --raid-devices=5 midway through the grow I recieved this in ...
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85 views

Fresh debian squeeze software raid install wont boot

I am following these instructions: http://www.iprobot.net/linux-tutorial/how-to-setup-software-raid-in-debian-ubuntu/ (I used debian-live-6.0.6-amd64-gnome-desktop.iso and DD'd that onto a usb key, ...
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43 views

Adding Additional RAID Array to Ubuntu 11.10 x64 Server

I asked this on askubuntu.com as well but since it's a server question, figured I'd throw it on SF, too. Haven't run into this situation before but it seems simple enough. Looking for advice/guidance ...
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280 views

Linux software RAID 10 array, failed drive, resize file system and migrate to a 3 drive RAID 1?

I have a software RAID 10 array which I recently noticed went into a degraded state. The OS is CentOS 5.8. It has 4x 500GB drives in 3 different arrays: /dev/md0 is RAID 1 and mounted to /boot (200MB ...
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579 views

Device in software RAID 10 array: clean, degraded. Ouch?

I've got 4x 500GB drives in software RAID. /dev/md0 is RAID 1 and mounted to /boot /dev/md1 is RAID 10 and is swap /dev/md2 is RAID 10 and is the main system and data device I looked at mdadm this ...
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2k views

mdadm stalls rebuilding a RAID5 array at 99.9%

I recently installed three new disks in my QNAP TS-412 NAS. These three new disks should be combined with the already present disk into a 4 disk RAID5 array, so I started the migration process. ...
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2k views

How do you set up RAID1 with both disks bootable on Debian/Ubuntu?

In Debian 6, new installation, what is the recommended way of setting up a software RAID1 array so that the system is bootable from both disks? I have heard that people that don't know what they are ...
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995 views

Ubuntu 12.04 LTS Update - With Error: “YOUR SYSTEM IS NOW UNBOOTABLE!”

I just did an apt-get dist-upgrade and saw the following error: cryptsetup: WARNING: failed to detect canonical device of /dev/md1 cryptsetup: WARNING: could not determine root device from /etc/fstab ...
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151 views

mdadm drive UUIDs chanaged, can they be changed back?

So I ran into this trouble and I believe I lost all my data..However I found an old mdadm --examine --scan file I made a month ago and an old mdadm.conf....Is it possible to use these two items to fix ...
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mdadm: Disk configuration by UUID

I want to create a soft RAID-5 and use UUIDs im the mdadm config file. So I have four disks with 1 partition each that spans the whole disk. But since the partitons don'5 have a filesystem, blkid does ...
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7k views

mdadm rebooted, array missing? can't assemble?

Not sure what is going on with my Array. I rebooted ubuntu 12.04.1 and got a error on startup that fstab couldn't mount the filesystem UUID I have for my mdadm array. After running a few commands a I ...
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197 views

Raid1 disk degraded after reboot

I'm testing a Rackspace cloud server and have two Cloud Block Storage volumes set up in a Raid1 configuration. There are no system files on these volumes, they're purely for storage. Everything ...
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324 views

Device cannot be added on software-raid-1 array on Ubuntu 12.04

Unfortunately all tutorials I have found online until now on how to setup software-raid-1 are outdated on ubuntu 12.40 My target is to setup it on a system with a secondary disk drive that is already ...
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662 views

reliably and automatically determine connection path of physical position of HDD from /dev/sdX device file

This is kind of a FAQ, but all the answers I found so far are not suited for full automation, which is what I need. So here it goes again. In Linux: Is there a reliable way to resolve the udev ...
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666 views

Software Raid 10 corrupted superblock after dual disk failure, how do I recover it?

I have a software raid 10 with 6 x 2tb hard drives (raid 1 for /boot), ubuntu 10.04 is the os. I had a raid controller failure that put 2 drives out of sync, crashed the system and initially the os ...
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172 views

RAID options with heterogeneous disks

I have a general purpose server which is running out of disk space. It currently has a RAID1 of two 2TB disks (WD RE4). So I'm going to buy two 4TB disks. I am considering the following options: ...
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296 views

Best redundant way to set up multiple drives of different sizes

I have a linux server (running Ubuntu 12.04 Server currently) that I need to set up multiple hard drives of differing sizes in primarily for media/backup purposes. The sizes are: 1x2TB 1x1TB ...
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1k views

Removing a device in “removed” state from Linux software RAID array

My workstation has two disks(/dev/sd[ab]), both with similar partitioning. /dev/sdb failed, and cat /proc/mdstat stopped showing the second sdb partition. I ran mdadm --fail and mdadm --remove for ...
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1k views

Is it reasonable to make a RAID-1 array with a ram disk and a physical disk to maximize read performance and protect data?

In one of the answers on SO (I forgot which one) I've seen a suggestion to make a RAID-1 array composed of a RAM disk and a physical partition. By adding the physical partition with --write-mostly and ...
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Is my hard drive about to die?

I have two hard drives set up as a RAID 1 array on my server (Linux, software RAID using mdadm) and one of them just got me this "present" in syslog: Nov 23 02:05:29 h2 kernel: [7305215.338153] ...
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293 views

Restoring data from a failed and possibly partly overwritten mdadm raid1

I have a failing hard disk (let's call it sda) which contains, among other things, a 1.5 TB partition (let's call it sda3). There is another disk (sdb), which has a 1.5 TB partition (sdb1) as well. ...
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How do I find out which disk in a multi-disk mdadm RAID1 triggered a rebuild?

I'm using mdadm for several RAID1 mirrors. md7 is an N-way mirror consisting of 3 spinning disks (all flagged write-mostly) and an SSD: md7 : active raid1 sdd1[0] sde5[3](W) sdf5[4](W) sdc1[1](W) ...
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613 views

How do I get rid of my duplicate GRUB entries? (Ubuntu 12.10, RAID1)

I have a Dell R300 machine running Ubuntu 12.10: $ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 12.10 Release: 12.10 Codename: quantal $ uname -a ...
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243 views

Cannot get at data in my NAS

I've got a bit of an issue that I'm hoping you can help me with. I have an Iomega ix4 as my NAS. This runs Linux and each drive in the box has 2 partitions: one for the OS and RAID info, and the ...
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758 views

How to detect hard disk failure?

So, one of my servers has a hard disk failure. It's running software RAID, the system locked up and according to /proc/mdstat (and /var/log/messages), it's really down: Personalities : [raid1] md2 : ...
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669 views

mdadm - Recovering a 'split' RAID1 array

I have two drives that used to be part of a single RAID1 volume but it appears that one of them went offline for some time, something I've noticed just now when I rebooted my system. I now seem to ...
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1answer
993 views

mdadm+zfs vs mdadm+lvm

This may be a naive question since I'm new to this and I cannot find any results about mdadm+zfs, but after some testing it seems it might work: The use case is a server with RAID6 for some data that ...
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834 views

Linux software RAID6: 3 drives offline - how to force online?

This is similar to 3 drives fell out of Raid6 mdadm - rebuilding? except that it is not due to a failing cable. Instead the 3rd drive fell offline during rebuild of another drive. The drive failed ...
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262 views

Shell Script To Monitor Completion of RAID Assembly

How can I pause execution of my shell script after calling the following command until the raid array has been assembled? From what I understand, this is an asynchronous process and status of the ...
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693 views

Linux Software RAID1 Rebuild Completes, but after reboot, its degraded again

I have been beating my head with an issue here, and I'm now turning to the internet for help. I have a system running Mandrake Linux, with the following configuration: /dev/hda - This is a IDE ...
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1answer
272 views

How to get started troubleshooting Linux mdadm raid10 write performance?

Using Linux mdadm, I've setup a six disk raid10,f2 array. I'm using 7200RPM SATA drives. The biggest load I am worried about is recording four streams of live video (worst case of 20Mbits each, final ...
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608 views

Controlling mdadm faulty disk rebuild order in RAID 10 array

I have a Linux mdadm RAID 10 array comprising of 6 (SATA) disks configured with n2 copies. While pulling out one disk, another one in another mirror pair failed. Leaving me with: $ cat /proc/mdstat ...
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RAID1: Which disk will be mirrored?

How does a RAID1 system determine which disk to use as the source and which disk to use as the destination when mirroring? Assume for instance the following scenario: A RAID1 array is created with ...
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620 views

Recovering a mdadm+lvm+ext4 partition with read error

One of disks in my NAS has failed. The NAS is running Linux, and it uses mdadm + LVM technology for its filesystems. I do have backup for most of the contents, but not for the very last changes, and ...
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556 views

Risky to have RAID5 with 3x3TB drives? What alternatives should I be considering?

A drive dropped out of my raid 5 array yesterday. It looks like the reason was due to a bad controller so I switched it out and attempted to re-add the drive but mdadm claimed it couldn't do it. So I ...
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596 views

raid10 in mdadm reports incorrect “Used Dev Size”

I previously had a raid5 with mdadm using four 2TB drives. I've recently disassembled the raid and created a raid10 with six 2TB drives, but mdadm --detail is showing "Used Dev Size" as only 2TB (the ...