A linux utility used to manage software RAID devices.

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Linux Software RAID10: Mysterious renaming /dev/md0 to /dev/md127: Why?

During the last two nights we had mysterious events on a server running Ubuntu Linux 12.04 LTS with a Linux mdadm software RAID10: DeviceDisappeared /dev/md0 NewArray /dev/md127 Both messages ...
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265 views

recover highly degraded raid array

I have a Linux RAID6 array (mdadm) composed of 8 disks. 2 disks failed. I replaced them, now I have 2 new empty disks. I would like to rebuild the raid but when I start a raid rebuild, the rebuild ...
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2answers
41 views

How Do I resize a partition? [on hold]

I have the following FIle system setup currently. I need as much room as i can get in ./home. root@Jm2:~# df -h Filesystem Size Used Avail Use% Mounted on /dev/md1 20G 7.6G 11G 42% ...
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27 views

Recently installed RAID already degraded on partition

I set up setting up a new two disk RAID1 which appeared healthy in mdstat. In a few hours, here's what I later saw when I ran cat /proc/mdstat. Personalities : [raid1] md1 : active (auto-read-only) ...
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14 views

mdadm set the mode before a second device raid1?

i have a problem. server use two disk softraid1. disk sda is die, and replaced disk. and reboot now, copy partition table sdb to sda ok. next step copy boot record sdb to sda ok. finaliy add sda in ...
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19 views

Best way to remove drives from MDADM raid array

I have a situation with a RAID array; I'm concerned that the drives in the array are going to fail soon, and given their age, I would rather replace them sooner than later. The problem I have, is ...
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44 views

mdadm - RAIDs of partitions or partitions of RAID?

If using entire drives for an mdadm RAID which will be the boot device as well, is it more correct / standard to: 1) Configure the RAID out of partitions that encompass the whole drive (like ...
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83 views

RAID1 - mdadm mirror - not performing parallel reads as expected?

We have a three-way RAID 1 mirror which is powered by mdadm. I think I read that mdadm is supposed to take multiple simultaneous read requests and distribute them across different drives in the ...
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35 views

RAID1 write penalty using mdadm - what's the cause?

When doing some performance tests writing to a SSD-based 3-way RAID 1 mirror powered by mdadm, it appears we suffer a significant write penalty of about 2.2x slower than doing the same test on just ...
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1answer
49 views

Power outage during RAID1 build [closed]

I was 60% complete building a two-disk RAID1 on my Ubuntu 14.04 server with the command sudo mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sdb1 /dev/sdc1 when I accidentally ...
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23 views

How to tell mdadm to use a partition as/instead of a block-device?

I have four 500GB disks which were set up as a Linux Software-RAID 5 volume during the Debian install (next to the system drive which is a SSD). One of the drives (sda) went bad and now I am trying to ...
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34 views

How/When to physically remove a failing harddrive after replacing it in a Linux RAID?

I have a Linux software RAID-1 with mdadm. Similar to this question ("How to safely replace a not-yet-failed disk in a Linux RAID5 array?"), I want to replace a disk in a the raid. My question might ...
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40 views

Growing RAID0 to RAID5 sync delayed

I've recently switched my NAS with a single 4 TB disk to a RAID setup, with the goal of implementing a 3-disk RAID5. To do this without a 4th disk and without loosing my data, I first set up the 2 new ...
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Q: MDADM mismatch_cnt > 0. Any way to identify which blocks are in disagreement?

Okay. After a routine scrub, my MDADM RAID5 is reporting mismatch_cnt = 16. As I understand, this means that while no device reported a read error, there are 16 blocks for which the data and parity ...
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1answer
47 views

Is it possible to recover a RAID 5 in this case?

Is it possible to recover a RAID 5? After losing the "/proc/mdstat" and run by mistake "mdadm --create --verbose /dev/md0 --level=5 --raid-devices=4 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1" instead of ...
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1answer
69 views

Can't mount my hard drive

When I try to mount one of my hard drives, it can't locate the folder with the hard drive. This is the output for the command df: Filesystem 1K-blocks Used Available Use% ...
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2answers
102 views

mdadm RAID6, recover 2 disk failure during reshape

I was reshaping my array from 10 disks to 11 to a degraded state (drive I want to add already has data on it, but nowhere to put it). 2 drives disconnected while it was running (power issue). Is it ...
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45 views

Write cache settings not working

I am using Debian 8.0 x64 with 72 GB of RAM with 4 drives configured as software RAID 0. Linux s1 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt11-1 (2015-05-24) x86_64 GNU/Linux I tried setting dirty ...
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243 views

mdadm, RAID5 all disks marked as spare, won't start

RAID5 config with mdadm and 4 disks After some incidents, eg one of the drives was lost, had to reboot the server and rebuild the array, my raid is in a funny situation cat /proc/mdstat ...
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41 views

mdadm and LVM high load and IOwait

I've got a new CentOS 6.6 server with 2 HDD with mdadm & LVM. As I've used the CentOS install CD I assume everything should be aligned properly. I've just written a KVM image to a LVM LV using dd ...
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107 views

Mount a NTFS Raid0 disk under linux debian

In my new laptop I have a a RAID 0 configuration with a normal disk and a smaller SSD drive. I have removed the dvd bay and replaced the dvd player with a 256 GB SSD drive where I run linux debian. I ...
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93 views

RAID 5 reshape freeze

I recently added a new disk to my RAID5 array and started growing it. Absent minded as I am I rebooted the server during this reshape process I as another program was hung and blocking some ports. ...
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68 views

Proper way to identify member devices in mdadm.conf

My current mdadm.conf looks like: $ cat /etc/mdadm/mdadm.conf DEVICE /dev/sdb1 /dev/sdc1 ARRAY /dev/md0 metadata=1.2 spares=0 UUID=357ff7cc:55e78d18:9fc7917b:f5b253f2 MAILADDR me@example.com Since ...
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1answer
58 views

How to add disk back to RAID and replace removed

Received a message that RAID went into degraded state: Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid1 sda1[0] sdb1[1] 524224 blocks ...
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227 views

Hard disk / SSDs - detection and handling of errors - is silent data corruption reliably prevented?

When an error occurs on a drive, is it correct to assume that it will always be detected and reported to the OS (if software RAID such as mdadm) or RAID controller (if hardware RAID) as a failed read ...
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57 views

Where do md array definitions come from?

I created a md array in an ARM computer with two USB/SATA disks in RAID 1. Then I moved both disks to my Ubuntu desktop and installed mdadm. Installation detected the RAID and added the definition to ...
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Can't see other VHDs after detaching another. Azure Ubuntu VM

We have encountered high Disk IO on our Ubuntu 14.04 VM's running mongoDB. On Windows Azure. To solve this issue we have changed the VM size from A2 to A3 (to add the additional data discs) and ...
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43 views

MD RAID Array Often Starts Without All Drives

I find that, when I start/restart my system, my MD array often doesn't start with all of the drives even though the device-names haven't changed at all. I'll have to stop the array and reassemble it, ...
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163 views

Ubuntu RAID1: How to boot after (physically) removing /dev/sda? (mdadm, Grub2)

Several months ago I installed Ubuntu 14.04.2 Server (x64) with RAID 1 using the following instructions: https://help.ubuntu.com/lts/serverguide/advanced-installation.html I followed the ...
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93 views

Linkstation WXL: RAID disappeared, /dev/md2 is inactive - how to troubleshoot

today I had problems accessing the SMB-share on my Linkstation. My NAS has two hard drive disks, configured as raid0. this raid was mounted to /mnt/array1/intern - the folder that i am missing. My ...
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42 views

Software RAID 1 does not extend on two new additional drives

I added two new devices two my software RAID 1 system. They are recognized by mdadm but I can't use the addition space. Here is how I proceed: I added the two new disk to my PC and created on each ...
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38 views

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 ...
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1answer
53 views

Remove a drive from a 2-drive RAID 5 array using version 1.2 metadata?

My situation is nearly identical to "How to remove a drive from a non-standard 2-drive RAID 5 array?", except my 2 TB RAID5 is using mdadm super block version 1.2. According to the best answer, ...
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76 views

Resetting root password on Slackware (software RAID)

I'm trying to reset password to root account on Slackware server (with Intel Atom on Intel motherboard and two HDDs). There is software RAID set up (devices mounted during boot: md0 - /, md1 - /usr, ...
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38 views

Recover overwritten RAID5 array (XOR)

as I've mentioned in a recent question (RAID5 rescue with LVM2 running on it) I'm rebuilding an RAID5 array. Now, I think that the initial wrong mdadm --create ... command has started the ...
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1answer
42 views

Shrinking LVM Volumes

We have a Synology RS3614rpxs NAS head containing (9) 3TB hard drives in a RAID 6 + 1 hot spare. The storage became exhausted and we added an expansion chassis where 5TB hard drivers were installed ...
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274 views

Can mdadm convert a RAID5 to a RAID1?

I have a RAID5 consisting of 3 disks, one of which is broken. I was wondering if it is possible to convert those two disks to a RAID1 without data loss and without having to back-up the data ...
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65 views

Software Raid: Array inconsistent state

I'm running software raid 1 with md on debian distro. One of the disks has failed, but not all of the raid arrays were at that time in a "fail" state. In order to bring them also in a fail state (in ...
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250 views

CoreOS on software RAID with EXT4 filesystem

I'm currently thinking about installing the CoreOS on a bare-metal server with two disks I want to put in a software RAID1. The latest CoreOS is now using EXT4 as their default filesystem and I'm ...
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70 views

Rescue mdadm RAID 6 array after three disk events

mdadm 3.2.5, 14 disk RAID 6 Had a drive failure Friday. Two more today in rapid succession. All drives seem fully operational. This is roughly 40TB array, I could use your help please to rescue ...
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4answers
366 views

mdadm 3-way RAID 1 - good solution for guaranteed 2-drive failure tolerance?

Is a 3-way RAID1 using mdadm a good solution to be able to sustain any two drives failing without the RAID failing? I know this costs extra in the sense of only being able to use 1/3 of the disk ...
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99 views

Grow individual drive size in RAID5 array

My array is built of 3 hard drive of 2TB, I have 2 more free space and I would love to start to grow my array with 4TB hard drives, if I start to put 2 4TB hard drives and eventualy replace the 2TB ...
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239 views

mdadm: activating spare and removing 'removed' disks

I added 1 disk to my raid array, started reshaping, and then remembered that I forgot to partition the drive. So I partitioned and readded the disk. I'd like to get rid of that 'removed' and activate ...
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698 views

Restore lost RAID1 volume on Synology with mdam

Several days ago I found my DS412+ in fatal state. Volume1 crashed, system volume too. Moreover, Volume2 disappeared from the system! It looks like Volume1 had no free space and cannot transfer data ...
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54 views

mdadm array keeps losing disks on separate SATA controller

My Ubuntu Linux server has an mdadm array (RAID 5) with four 2TB SATA disks that keeps "loosing" two disks from time to time. Rebooting and re-assembling the arrays has worked out fine up until now. ...
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259 views

How to setup Debian Jessie to boot from broken RAID1

I want to setup Debian Jessie in EFI-mode with a LVM on an LUKS on a RAID1. I tried it with the Installer but when i remove one of the hard drives the whole system isn't booting any more. What I ...
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211 views

mdadm: drive replacement shows up as spare and refuses to sync

Prelude I had the following devices in my /dev/md0 RAID 6: /dev/sd[abcdef] The following drives were also present, unrelated to the RAID: /dev/sd[gh] The following drives were part of a card reader ...
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64 views

Data recovery seems impossible after kernel upgrade. MDADM (Raid1) LVM2

I opened a question about rebuilding a bad partition My Problem that din't take me anywhere. Bad news is the company trying to rescue the data says it's finding huge inconsistencies they can see some ...
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1answer
122 views

How to rebuild Raid arrays after booting to a live cd?

Problem: Botched kernel upgrade left me with an unbootable system (don't ask me how it also made my backup kernel unbootable) where boot and root are on mdadm raid 1 arrays (with metadata 1.0/1.2 ...
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221 views

Disaster recovery. MDADM/LVM2 Some advance but stuck on final mount

We made a stupid upgrade on a running server using wrong repositories and the system became totally unbootable. The system, a SLES 11 we used a openSuse repository to upgrade, and everything went ...