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:

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

  • ImageMagick Convert PDF Not Authorized
  • ImageMagick Converted PDF to JPEG some files have a black background solution
  • Linux Mint Mate Customize the Lock screen messages and hide username and real name
  • Ubuntu/Gnome/Mint/Centos How To Take a partial screenshot
  • ssh how to verify your host key / avoid MIM attacks
  • Cisco IP Phone CP-8845 8800/8900 Series How To Reset To Factory Settings Instructions
  • ls how to list ONLY directories
  • How to encrypt your SSH private key file id_rsa
  • Linux Mint 18 Disable User Name List from showing on Login Screen
  • Firefox Cannot Hit Enter Key In Address Bar and Location History Not Working
  • Cisco Unified Communications Manager / CUCM IP 8.6,10,12 Install Error Solution
  • Ubuntu Debian Mint Linux SSHD OpenSSH Server Not Starting After Reboot Solution
  • nmap how to scan for all ports and not just the 1000 most common ports
  • Windows 7,8,10 and Server 2008, 2012, 2016, 2019 Read Only Attribute Won't Go Away
  • bind / named how to make a wildcard record and retain defined A records
  • Cisco Unified Communications Manager 12 Install Errors on Proxmox/KVM
  • Local Vs Universally Administered MAC Address NIC Refuses to come up
  • Cisco Unified Communications Manager 12 CUCM 12 - How To Enable Video Calling
  • Windows 7, 8, 10, Windows Server 2008, 2012, 2016, 2019 How To AC97 Audio Drivers and Other Unsigned Drivers
  • Cisco Unified Communications Manager / CUCM IP Telephony Definitions