A linux utility used to manage software RAID devices.

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In mdadm's /proc/mdstat, what does [U_U] mean?

I just set up a raid 5 array for my media server. I set got 2 new disks, and set up an array with one missing drive, to copy the data from the old single drive to the new array, and later I will add ...
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448 views

ext4 on mdadm reverting data

I have a problem with my home server setup. The problem is that sometimes, but really rarely, it reverts (for a lack of a better term) all my data back to an earlier state (somewhere between months ...
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128 views

Disaster recovery for RAID and mdadm

I´m having a software raid 5 with 5 2TB members. After some work with gparted my RAID doesn´t work any more... How can I check the integrity of each member? What would be my options, if the partition ...
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Optimal raid array on Centos 6

I have 4x2TB disks and I want to create a well-performing RAID5 array (server is HP N40L microserver with 8GB RAM, booting from a 64GB SSHD). The OS is Centos 6.3, x86_64. I created the raid array ...
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651 views

Cloning Ubuntu mdadm RAID1

I would like to clone a pair of RAID1 drives created with mdadm. I've tried Clonezilla, but there's no native support for mdadm, so it resorts to using dd which is incredibly slow. I've looked for ...
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758 views

Linux raid10 on btrfs

I've read that BTRFS requires at least 4 disks (https://btrfs.wiki.kernel.org/index.php/Using_Btrfs_with_Multiple_Devices). Indeed, Linux mdadm raid10 requires only 2 disks ...
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Degraded RAID5 and no md superblock on one of remaining drive

This is actually on a QNAP TS-509 NAS. The RAID is basically a Linux RAID. The NAS was configured with RAID 5 with 5 drives (/md0 with /dev/sd[abcde]3). At some point, /dev/sde failed and drive was ...
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282 views

how to boot without assemblying raid arrays (or assembling them correctly)

I had one debian 6 system with two harddisks on raid1 set up via mdadm. built on simple partitions (/dev/sdb3, /dev/sdc3). at least on the old system, everything is tied up via UUIDs. then i inserted ...
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Software RAID 1 resync's on SATA cable switch?

I made a mistake when I opened up my desktop removed a 2 disk RAID 1 and reconnected them, but with the SATA cables switched, such that sda became sdb and viceversa. On boot, the RAID array started ...
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Post raid5 setup reboot shows single hard drive failure on ubuntu 12.10?

I just set up raid 5 on linux using three HDDs as per a guide. It all went fine until when I rebooted I got the following text: http://i.stack.imgur.com/Zsfjk.jpg. Does this mean one of my HDDs has ...
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809 views

Linux system cannot find RAID 10 md device after reboot of the system

I ran these commands: $ sudo mdadm --verbose --create /dev/md0 --level=10 --chunk=256 --raid-devices=4 /dev/sdh1 /dev/sdh2 /dev/sdh3 /dev/sdh4 $ echo 'DEVICE /dev/sdh1 /dev/sdh2 /dev/sdh3 /dev/sdh4' ...
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112 views

How to create physical and logical volumes on system reboot

My system is set up so that I take four devices, create a RAID 10 array out of them, create a physical volume, a volume group, and then three logical volumes, and lastly I create filesystems out of ...
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Does TRIM avoid the performance impact of mdadm RAID 1 on SSD?

It has already been mentioned in other questions that Red Hat recommends against using mdadm RAID 1 on SSD. Red Hat also warns that software RAID levels 1, 4, 5, and 6 are not recommended for use ...
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1answer
861 views

SSD lifetime in software RAID 1 [closed]

We're looking at use two SSD in a software RAID 1 raid on CentOS. We have tested performances and it is the same as a SSD alone. But we fear that because of mdadm, lifetime of the SSD will shorten. ...
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Solution for storing sata drives outside of case

I have a system that has 8 sata disks in a software raid 5 array using mdadm. My issue is that I want to move the drives from inside of the computer case in order to cool more efficiently. I have ...
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50 views

Do a Re-Build During a Re-Shape?

On my Linux software RAID 6 array, I'm currently mid-reshape and 2 drives have been marked as failed. I've swapped them out and added new ones to the array, which are currently marked as spares. The ...
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110 views

Linux RAID Re-Shape Stopped

For the past 8 hours my mdadm re-shape process has been stuck. The output is: Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [multipath] md0 : active raid6 sdo[11] ...
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How to add new partition to RAID-1 array on Redhat FC10?

I have a RH FC10 system with RAID 1 partitions, here is mdadm.conf: # mdadm.conf written out by anaconda DEVICE partitions MAILADDR root ARRAY /dev/md1 level=raid1 num-devices=2 metadata=0.90 ...
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174 views

Disable writing RAID degraded mode

I have a RAID5 with 5 disks on my machine and suspect the motherboard chipset to fail at some points and make my raid going in degraded mode. Last time it happened I noticed it on the failure of the ...
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1answer
8k views

How can one setup RAID 1 in Linux Mint 13?

I am trying to setup a Linux Mint 13 system using mdadm, with 2 1TB hard drives for a software mirror. I have tried following instructions found for Linux Mint 12, but the instructions fail to mention ...
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How to force mdadm to stop RAID5 array?

I have /dev/md127 RAID5 array that consisted of four drives. I managed to hot remove them from the array and currently /dev/md127 does not have any drives: cat /proc/mdstat Personalities : [linear] ...
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Resize underlying partitions in mdadm RAID1

I have a home built NAS, and I need to slightly reconfigure some of my drive usage. I have an mdadm RAID1 composed of two 3TB drives. Each drive has one ext3 partition that uses the entire drive. ...
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Can a non-redundant RAID5 cause any serious problems (compared to RAID0)?

I used to have a three-disc RAID5 (mdadm) in my computer for personal media storage (music, videos, photos, programs, games, ...). It had three discs with 750 GB each, resulting in an array capacity ...
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mdadm: superblock on /dev/sdd1 doesn't match others - assembly aborted

OS: Debian Squeeze Kernel: 2.6.32-5-amd64 mdadm version: 3.1.4 (31 August 2010) mdarrays md1 = raid1 (this is working) (devices: /dev/sd[fg]1) md0 = raid6 (previously raid5, ...
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Migrate mdadm raid array from 32bit to 64bit debian squeeze

I have a raid5 array running on Debian Squeeze 32bit (x86) and I plan to upgrade to Debian Squeeze 64bit (amd64). To keep my raid5 array and ext4 filesystem I simply keep a copy of my mdadm.conf ...
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1k views

Take one disk of external mdadm data raid 1 to travel

I have a mdadm software raid 1 on external disks with media data. For travel I want to take the data with me. I imagine to set the raid and the underlying filesystem in readonly mode and take just ...
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mdadm Ubuntu 12.04 fails to assemble RAID6 during boot

I will try to keep this short. I have a mdadm RAID 6 with 11 drives. This has for years "just worked" across reinstalls and such, without any issues. I have not even had the need for configuring ...
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177 views

How to grow an EBS mdadm raid 10 array?

Is it possible to grow a RAID 10 array? Can I take it offline and grow it? Or do I have to make an entirely new array, and copy all the data onto it?
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1answer
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How do I tell mdadm to start using a missing disk in my RAID5 array again?

I have a 3-disk RAID array running in my Ubuntu server. This has been running flawlessly for over a year but I was recently forced to strip, move and rebuild the machine. When I had it all back ...
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How do I reinitialise a failed RAID 5 drive using terminal on Ubuntu Server

I've currently put together a new system and part of that has been creating a software RAID 5 using 'mdadm' in Ubuntu Server. I successfully got to the point where I create the array using: sudo ...
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mdadm RAID Fast Setup with Empty Drives?

I am recreating some RAID5 disks as RAID6 with mdadm. There is no data on the drives that I care about. Setting up RAID takes a while to setup the shape - I accept that when there there is data that ...
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Simple mdadm RAID 1 not activating spare

I had created two 2TB HDD partitions (/dev/sdb1 and /dev/sdc1) in a RAID 1 array called /dev/md0 using mdadm on Ubuntu 12.04 LTS Precise Pangolin. The command sudo mdadm --detail /dev/md0 used to ...
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mdadm recognizing array incorrectly how can I recover the data

So I formatted both disks sd[cd], each as a big ext4 partition, and then used mdadm to create a raid0 array sd[cd]1. This worked fine, and I mounted the device and started storing data on it. Prior to ...
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642 views

Getting advanced format drives to like new?

I have 5 2TB WD Green (WD20EARX) drives that I eventually want to put into software RAID 5. I can't seem to find a complete guide on getting these drives prepared for use with Ubuntu (mdadm) that ...
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778 views

Safety of Truecrypt for Large Raid5 using ubuntu, mdadm, lvm, ext3?

I'm planning to set up a large (probably 6-9Tb) raid-5 array on ubuntu using mdadm, lvm and ext3. Does anyone have any opinions or suggestions on the safety of using a Truecrypt volume for that amount ...
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839 views

Adding Space to RAID5 using mdadm, lvm and ext3

I have seen a few descriptions about using mdadm with lvm to create an easily expandable raid, such as this question, but I still think I'm missing something. Say that I create the raid using mdadm ...
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Linux software RAID robustness for RAID1 vs other RAID levels

I have a RAID5 array running and now also a raid1 that I set up yesterday. Since RAID5 calculates parity it should be able to catch silent data corruption on one disk. However for RAID1 the disks are ...
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Can I use an entire drive for as a software raid member?

Can I use /dev/sda and /dev/sdb for my RADI1 configuration? Or do I first have to partition both with a single Linux raid partition?
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Recover data from RAID 0 disk images

I have four (4) disks which are in RAID 0, but the (Lacie) hardware enclosure failed and I'm trying to recover the data stored. I'm now trying to rebuild the RAID to access the data stored, but can't ...
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mdadm: hot remove failed

My RAID1 is degraded and I need to replace /dev/sdb. However, I could mark /dev/sdb5 (in /dev/md1) as failed and removed it, but I can't do the same with /dev/sdb1 (/dev/md0 which is mounted on /): ...
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mdadm raid5 read error not correctable

I have a software raid5 setup existing of 4 disks. sda, sdb, sdc, sdd Since everything was up and running I wanted to test the array. To do this I pulled the plug on one of the disks (sdd). Everything ...
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1answer
142 views

How to identify raid1 disks

I would like to know how mdadm identifies physical disks of raid1 . I think it is managed by uuids not device file like /dev/sdc2 /dev/sdd2. But I can`t confirm such information of raid1.
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Does RAID1 increase performance with Linux mdadm?

I have a cheap 2-bay NAS with a 2TB HDD. To be robust against disk failure, I'm thinking of buying a second 2TB HDD and putting it in RAID1 with Linux mdadm. The file system is ext4. Will this ...
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Fault tolerant RAID6 / RAID10 design for home server - not performance critical

I want to balance disk space against fault tolerance. I would like fault tolerance to be able to handle multiple disk failures (as I may not be able to afford replacements disks or have the time for ...
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How does one enable --write-mostly with Linux RAID?

Unfortunately the mdadm and mdadm.conf man pages are not quite up to par. I would like to enable the --write-mostly flag for my RAID, but neither the man pages nor the internet will tell me how. I am ...
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4answers
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How do I mount a software RAID1 (mirror) created by windows in Linux using mdadm?

I'm switching my Windows server to Ubuntu and am trying to get my software RAID1 (mirror) that I created in Windows to show up in Ubuntu. I have read that this is possible here using mdadm, but I'm ...
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1answer
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degraded mdadm RAID5 array

My /dev/md0 array just died last night. I got this email This is an automatically generated mail message from mdadm running on A Fail event had been detected on md device /dev/md0. It ...
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Is it possible to safely get data off a hard drive thats a member of a mdadm-mounted RAID1 array via USB?

I have a RAID1 array of two drives created with mdadm. Is it possible to remove one of the drives, hook it up to a USB SATA adapter, and safely mount it, get the info off of it, and return the drive? ...
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Btrfs on top of a mdadm raid10, or btrfs raid10 on bare devices?

I have a RAID10 managed by the mdadm and I have EXT4 filesystem on top of it. However, I like BTRFS and would like to convert the EXT4 filesystem to BTRFS, but I was thinking about performance and ...
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2answers
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How to remove a drive from a non-standard 2-drive RAID 5 array?

There is some information available on shape changes in RAID arrays but I'm a little nervous and would like confirmation: Problem: I have 2 500GB drive as software raid 5 (mdadm). I would like to ...