A linux utility used to manage software RAID devices.

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24
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4answers
47k views

How can I make mdadm auto-assemble RAID after each boot?

I successfully created a RAID (mirroring) by utilizing mdadm. However, I must run the following commands after each boot: mdadm --stop --scan // to stop /dev/md127 - I don't know where the number 127 ...
20
votes
8answers
93k views

How to get an inactive RAID device working again?

After booting, my RAID1 device (/dev/md_d0 *) sometimes goes in some funny state and I cannot mount it. * Originally I created /dev/md0 but it has somehow changed itself into /dev/md_d0. # mount ...
19
votes
8answers
26k views

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 ...
11
votes
3answers
22k views

How-to change the name of an MD device (mdadm)

Here is the output from mdadm -Esv: ARRAY /dev/md127 level=raid0 num-devices=2 UUID=d89d9d45:9a420812:c44c77eb:7ee19756 devices=/dev/sdb8,/dev/sda8 This is a v0.90 array. The question is as ...
9
votes
2answers
3k views

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 ...
8
votes
3answers
32k views

How do I reactivate my MDADM RAID5 array?

I've just moved house which involved dismantling my server and re-connecting it. Since doing so, one of my MDADM RAID5 arrays is appearing as inactive: root@mserver:/tmp# cat /proc/mdstat ...
7
votes
4answers
7k views

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 ...
7
votes
3answers
4k views

Raid1 with active and spare partition

I am having the following problem with a RAID1 software raid partition on my Ubuntu system (10.04 LTS, 2.6.32-24-server in case it matters). One of my disks (sdb5) reported I/O errors and was ...
6
votes
2answers
4k views

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 ...
6
votes
3answers
15k views

Creating a RAID1 partition with mdadm on Ubuntu

I'm trying to set up a RAID1 partition on my Ubuntu 9.10 workstation. On this dual-boot system, Ubuntu is running from a separate drive (/dev/sdc - an SSD that is quite small, which is why I need ...
6
votes
4answers
7k views

mdadm volume works, but won't assemble/mount on startup?

I have an mdadm/lvm2 volume with 4 HDs that I created in Ubuntu 10.04. I just upgraded the computer to Ubuntu 10.10. I redid the mdadm commands to get volume up and running, did mdadm --detail --scan ...
6
votes
2answers
2k views

Is it safe to put harddisks of a md-software-raid to standby?

I have a home-fileserver with 6 desktop harddisks in a md-raid. The server isn't accessed a lot, so I think it would be good for the harddrives to go in standby-mode after some idle time (e.g. with ...
5
votes
2answers
3k views

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 ...
5
votes
1answer
3k views

Possible mdadm RAID states?

I'm writing a monitoring plugin for a home server RAID, mdadm on Ubuntu 10.4. Using sudo mdadm --detail /dev/md0 I get output like this: /dev/md0: Version : 00.90 Creation Time : Thu Dec ...
5
votes
2answers
398 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 ...
5
votes
2answers
4k views

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. ...
5
votes
1answer
149 views

Is it safe to “use” to disk if extended smart check is in progress?

As simple as the title suggests. /dev/sda is a unit from /dev/md127 - RAID1 drive. I'm currently running a test - started a smartctl -t long /dev/sda. Afterwards, I started to copy files over ...
5
votes
1answer
1k views

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 ...
4
votes
5answers
9k views

Adding drives to a RAID 10 Array

How would I grow a RAID10 array using mdadm? Obviously I would need to add 2 drives at a time, or would it have to be 4 drives? I have a feeling its just a bad idea. Or would be just wiser to just ...
4
votes
2answers
2k views

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 ...
4
votes
1answer
308 views

HDDs occasionally “click” and dump this error

Every once in a while, my HDDs (6 1TB drives in a Linux md RAID-6 array) make a brief "click" sound, and I get this from dmesg. I don't really have any clue how to start diagnose this, or even how ...
4
votes
4answers
2k views

Need to find which drives are mirrored within RAID-10 array

I have a home media server running on openSUSE 12.2. I'm using eight 2TB drives in a RAID-10 configuration. I deliberately bought two different types of drives: four Seagate Barracuda Green and four ...
3
votes
2answers
129 views

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 ...
3
votes
2answers
275 views

What would you see if you tried to mount a single drive from a RAID 5 Array?

The title pretty much sums it up - if someone were to mount a single drive from a software RAID 5 array, what would they see? Would it point to being part of a RAID array, appear as encrypted data, or ...
3
votes
3answers
164 views

Can RAID5 drives be defective while passing self-tests?

I have a 4-drive RAID5 in Ubuntu 10.10 with mdadm. One of the disks seems to be problematic. It dropped from the RAID, and I re-added it and it was fine for a while, but now when I re-add it I get a ...
3
votes
1answer
839 views

mdmda raid 1 - spare drive after SATA cable change

Yesterday my hoster changed a SATA cable of one of my hdds, when my server came back up again cat /proc/mdstat showed this Personalities : [raid1] md124 : active raid1 sda1[0] 4193268 blocks ...
3
votes
0answers
196 views

mdadm: Win7-install created a boot partition on one of my RAID6 drives. How to rebuild?

My problem happened when I attempted to install Windows 7 on it's own SSD. The Linux OS I used which has knowledge of the software RAID system is on a SSD that I disconnected prior to the install. ...
3
votes
2answers
1k views

mdadm: safest way to grow RAID 5 (4x2TB) with 2x4TB

My situation:I am currently running a RAID 5 with 4x2 TB disks and would like to grow the array with 2 x 4 TB disks. The goal would be that there is a RAID 5 with 4 x 4 TB (the two 4 TB disks and two ...
2
votes
4answers
1k views

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 ...
2
votes
3answers
1k views

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?
2
votes
4answers
819 views

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 ...
2
votes
1answer
379 views

MDADM RAID-0 does not increased size after grow on AWS Linux with EBS

I wanted to grew a Raid0 from 2 disks to 3 (each 1TB EBS on Amazon AWS) but the size did not change thereafter. The RAID started with two disks sdc and sdd and the new one was sdf. Here is the ...
2
votes
3answers
3k views

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 ...
2
votes
2answers
963 views

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 ...
2
votes
2answers
10k views

How to remove Linux software RAID MD device?

I'm trying to install openSUSE 12.3 on the new server. It is this machine. There are 2 HDDs connected to the SAS controller. What I want to achieve is a NON-RAID configuration where 1.HDD is used for ...
2
votes
1answer
104 views

Why make a partition at all for mdadm/raid?

i have 4 disks, sd[a,b,f,g] of various sizes that I want to 'merge' together. I am using mdadm to achieve this. my question is, what's the difference between -- mdadm --create /dev/md0 ...
2
votes
1answer
2k views

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 ...
2
votes
1answer
2k views

Auto-rebuild RAID6 with MDADM

I have an openSUSE 11.3 Linux computer with 5 disks of 1TB (WD enterprise disks) in it. With mdadm I configured a RAID6 device. Now, after a lot of thorough testing, I've noticed that when the ...
2
votes
1answer
286 views

convert full-disk RAID5 array to partition-based array?

I have a RAID 5 array, md0, with three full-disk (non-partitioned) members, sdb, sdc, and sdd. My computer will hang during the AHCI BIOS if AHCI is enabled instead of IDE, if these drives are plugged ...
2
votes
2answers
251 views

Removing a disk from an Ubuntu mdadm RAID marks the array as inactive, instead of degraded

I'm setting up a mdadm raid 1 array on Ubuntu 14.10 under VirtualBox. Everything works fine: The raid 1 is set up with /dev/sdc1 and /dev/sdd1: Personalities : [linear] [multipath] [raid0] [raid1] ...
2
votes
2answers
2k views

Convert RAID 1 to RAID 10 in mdadm

In my current Ubuntu server, I have 2x 2TB Western Digital RED hard drives in a RAID 1, using mdadm. I would like to add 2 more 2TB RED drives, and convert it to a RAID 10. I realize I would have to ...
2
votes
1answer
3k views

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, ...
2
votes
2answers
312 views

Recover from failed recovery of software RAID5 failure

I have the pleasure ;-) to have been handed the task to try to get data off a server that had a RAID5 array problem and a failed attempt to recover it. Background: the computer in question is some ...
2
votes
1answer
2k views

how can fsck to recover from hardware failure?

I have a RAID 5 array using mdadm and ext4 as its filesystem. We got a strong power surge and one of the drive faulted, while another one got a bit flakky, aka "click of death". I replaced the disks ...
2
votes
2answers
661 views

Linux drive permissions for disk used by two systems

I've got a large mdadm-based RAID5 array that I've been using with an Ubuntu 8.04 system. I'm setting up a new 9.10 (alpha 6) system on the same hardware. mdadm does a great job automagically ...
2
votes
1answer
9k views

Ubuntu Server 14.04 - RAID5 created with mdadm disappears after reboot

This is my first question on superuser, so if I forgot to mention something, please ask. I'm trying to set up a home server which will be used as file server and media server. I installed Ubuntu ...
2
votes
1answer
1k views

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 ...
2
votes
3answers
1k views

RAID-1 and regular drive removal (using RAID-1 as a backup measure)

Is using mdadm's RAID-1 of 2 partitions (one on laptop's internal HDD, one on external HDD) a good idea. I want the system to work as RAID-1 if both drives are present, work as regular volume ...
2
votes
0answers
111 views

how to trim the SSD disk of an hybrid Linux soft RAID?

We are considering implementing an Hybrid Linux Raid with SSD+HD by using the "writemostly" flag that supposedly makes the raid write further to the HD than to SSD while maintaining the benefits of ...
2
votes
0answers
277 views

Redundancy: LVM+mdadm or LVM internal RAID

The task is to create LVM storage for virtual machine images. So LVM will be used in any case. There are two ways LVM providing redundancy: block mirroring lvcreate -m 1 --mirrorlog mirrored -n ...