A linux utility used to manage software RAID devices.

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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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29 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
46 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
48 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
67 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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31 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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2answers
145 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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25 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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64 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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1answer
62 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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1answer
46 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
42 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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3answers
158 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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2answers
55 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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0answers
16 views

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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36 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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106 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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1answer
67 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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1answer
39 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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30 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
47 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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1answer
60 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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1answer
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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2answers
241 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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54 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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205 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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1answer
61 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
275 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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89 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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145 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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1answer
489 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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2answers
51 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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238 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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1answer
138 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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62 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
67 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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1answer
175 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 ...
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3answers
66 views

In a software RAID1, why does tune2fs -c 0 /dev/sda1 not throw an error but change is not seen in tune2fs -l /dev/sda1?

The Title pretty much says it all. Turn off mount count fsck seems to succeed: tune2fs -c 0 /dev/sda1 tune2fs -c 1 /dev/md0 But listing out via tune2fs -l /dev/sda1 shows mount count is set back ...
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1answer
94 views

How to have automatic file system checks for Linux Software Raid?

In a Linux Software raid, what is the best practice for periodically having the filesystems checked? With single drive or hardware raid, tune2fs -c 5 -i 1w /dev/sda1 means check the filesystem every ...
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1answer
130 views

ThinkServer RD440 raid mess

Does anybody have experience dealing with raid config on these new Thinkpad servers? My problem is the following: In order to be able boot this server I must put the drives to RAID1 to create an SCM ...
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101 views

Can't rebuild a linux RAID array after replacing disk, “mdadm: Cannot open /dev/sdb1: Device or resource busy”

I have replaced a failed drive in my server with a new one, and wish to add it back to the array. I am getting the following error, what can I do to resolve this? [root@la ~]# cat /proc/mdstat ...
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518 views

CentOS 7: GPT and software RAID 1 without 'biosboot' partition

I have a CentOS 6 server with software RAID1 (2x3TB): - sda # parted /dev/sda unit s print Model: ATA TOSHIBA DT01ACA3 (scsi) Disk /dev/sda: 5860533168s Sector size (logical/physical): 512B/4096B ...
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1answer
34 views

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 ...
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1answer
237 views

mdadm: Convert RAID10 to RAID1

The machine in question is equipped with 4x ssd, and running Debian wheezy 7.8, linux kernel 3.2.0-4, mdadm v3.2.5. Currently I'm using a RAID10 consisting of all these ssd. I've to increase the ...
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1answer
120 views

Repairing RAID6 with two drive issues mdadm

I have had two disk failures on my RAID6 array. I have added two new disks and did the following: I ran mdadm /dev/md1 --remove on the two disks I set up my RAID on the 1st partition of each disk ...
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1answer
141 views

Best way to RAID 4 x Intel SSD 910 for PostgreSQL

I have a Linux (debian/ubuntu) server with 4 x Intel SSD 910 800GB pcie that I need to RAID together. The biggest problem with these card is that they give you 4x200GB drives that you cant ...
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1answer
65 views

Why is my HDD partition a character special device?

I have a bunch of old 1T disks with an mdadm array on them. They had been out of commission for awhile, but yesterday I slotted them into a server running an up to date Debian Jessie. Eventually I ...
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87 views

How to best use Amazon's “ephemeral” SSD devices under Linux? [closed]

Amazon attaches "ephemeral" SSD device(s) to most of the instace-types -- these are included in the cost of VM, are fast, but any data on them is lost, when the VM is shut down. How to make the best ...