mdadm Linux Software RAID QuickStart Guide

 

Create New RAID 1 Array:

First setup your partitions (make sure they are exactly the same size)
In my example I have sda3 and sdb3 which are 500GB in size.

mdadm --create /dev/md2 --level=1 --raid-devices=2 /dev/sda3 /dev/sdb3
mdadm: array /dev/md2 started.

Check Status Of The Array

*Note I already have other arrays md0 and md1.

You can see below that md2 is syncing at a speed of about 91MB per sec.

cat /proc/mdstat


Personalities : [raid1]
md2 : active raid1 sdb3[1] sda3[0]
      488287552 blocks [2/2] [UU]
      [>....................]  resync =  0.5% (2460992/488287552) finish=88.8min speed=91147K/sec
     
md1 : active raid1 sda2[0] sdb2[1]
      29302464 blocks [2/2] [UU]
     
md0 : active raid1 sdb1[1] sda1[0]
      58604992 blocks [2/2] [UU]
     
unused devices: <none>

Check the basic details of an array:



mdadm /dev/md0
/dev/md0: 55.89GiB raid1 2 devices, 0 spares. Use mdadm --detail for more detail.
/dev/md0: No md super block found, not an md component.


More Detail

mdadm --detail /dev/md0

/dev/md0:
        Version : 0.90
  Creation Time : Tue Aug 31 22:37:52 2010
     Raid Level : raid1
     Array Size : 58604992 (55.89 GiB 60.01 GB)
  Used Dev Size : 58604992 (55.89 GiB 60.01 GB)
   Raid Devices : 2
  Total Devices : 2
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Wed Sep  1 18:39:53 2010
          State : active
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0

           UUID : 7b4e9a42:823c7ee5:0d6ee1b8:30df68a8
         Events : 0.7

    Number   Major   Minor   RaidDevice State
       0       8        1        0      active sync   /dev/sda1
       1       8       17        1      active sync   /dev/sdb1

Update /etc/mdadm.conf File



mdadm --brief --detail /dev/md0

ARRAY /dev/md0 level=raid1 num-devices=2 metadata=0.90 UUID=7b4e9a42:823c7ee5:0d6ee1b8:30df68a8

To edit the /etc/mdadm.conf file directly just run the command like this make sure to use the ">>" or you will wipe out any existing array info.

mdadm --brief --detail /dev/md0 >> /etc/mdadm.conf

 


Tags:

mdadm, linux, software, raid, quickstart, array, partitions, sda, sdb, gb, dev, md, devices, arrays, syncing, mb, proc, mdstat, personalities, active, uu, resync, min, unused, gib, spares, component, creation, tue, aug, preferred, persistence, superblock, persistent, update, wed, sep, uuid, ee, df, raiddevice, sync, etc, conf, num, metadata, edit, quot, existing, info,

Latest Articles

  • ssh Too many authentication failures not prompting for password
  • LightDM Mint Ubuntu Debian won't start errors Nvidia Graphics
  • WARNING: Unable to determine the path to install the libglvnd EGL vendor library config files. Check that you have pkg-config and the libglvnd development libraries installed, or specify a path with --glvnd-egl-config-path. Linux Ubuntu Mint Debian E
  • How To Upgrade Linux Mint 18.2 to 18.3 to 19.x and 20.x
  • MP3s Won't Play / ID3 Version 2.4 Issues in Cars and Other MP3 Players/CDs/DVDs Solution
  • LXC Containers LXD How to Install and Configure Tutorial Ubuntu Debian Mint
  • GlusterFS HowTo Tutorial For Distributed Storage in Docker, Kubernetes, LXC, KVM, Proxmox
  • Ubuntu Mint audio output not working pulseaudio "pulseaudio[13710]: [pulseaudio] sink-input.c: Failed to create sink input: too many inputs per sink."
  • How To Shrink Dynamically Allocated VM QEMU KVM VMware Disk Image File
  • How To Enable Linux Swapfile Instead of Partition Ubuntu Mint Debian Centos
  • 404 Not Found [IP: 151.101.194.132 80] apt update Debian 11 Bullseye Solution The repository 'http://security.debian.org bullseye/updates Release' does not have a Release file.
  • WARNING: Can't download daily.cvd from db.local.clamav.net freshclam clamav error solution
  • (firefox:9562): LIBDBUSMENU-GLIB-WARNING **: Unable to get session bus: Failed to execute child process "dbus-launch" (No such file or directory) Solution
  • Debian Mint Ubuntu Which Package Provides missing top, ps and w Solution
  • Vbox Virtualbox DNS NAT Network Mode NOT working
  • Docker Tutorial HowTo Install Docker, Use and Create Docker Container Images Clustering Swarm Mode Monitoring Service Hosting Provider
  • Zoom Password Error 'That passcode was incorrect' - Solution Wrong Passcode Wrong Meeting Name
  • How To Startup and Open Remote/Local Folder/Directory in Ubuntu Linux Mint automatically upon login
  • How To Reset Windows Server Password 2019, 2022, 7, 8, 10, 11 Recovery and Removal Guide Using Linux Ubuntu Mint Debian
  • How To Create OpenVPN Server for Secure Remote Corporate Access in Linux Debian/Mint/Ubuntu with client public key authentication