engineering:computer_science:linux:linux_mdadm_software_raid

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision		 Previous revision
engineering:computer_science:linux:linux_mdadm_software_raid [2024/08/16 13:56] – removed - external edit (Unknown date) 127.0.0.1engineering:computer_science:linux:linux_mdadm_software_raid [2024/08/16 13:56] (current) – ↷ Links adapted because of a move operation carlossousa
Line 1: Line 1:
 +====== Using mdadm to create a Software RAID in Linux ======
 +
 +Part of [[engineering:computer_science:linux:linux|Linux]]
 +
 +===== Installation =====
 +
 +In Debian:
 +<code>
 +
 +sudo apt get install mdadm
 +
 +</code>
 +
 +=====   =====
 +
 +===== Partition Disks for mdadm usage =====
 +
 +You can use:
 +
 +<code>
 +sudo mdadm -E /dev/sd[b-c]
 +
 +</code>
 +
 +to check if the devices are part of a RAID / super-block is found.
 +
 +==== Drive Partitioning for RAID: ====
 +
 +<code>
 +sudo fdisk /dev/sdX
 +
 +</code>
 +
 +To create the partition, input the following values in order. Each Input should be followed by a confirmation (ENTER)
 +
 +^Value^Description|
 +|n|New primary Partition|
 +|P|Define as Primary Partition|
 +|1|Partition Number|
 +|(ENTER)|Confirm Default Starting Block|
 +|(ENTER)|Confirm Default End Block|
 +|t|Choose partitions type|
 +|fd|Partition type: Linux Raid auto|
 +|w|Write Changes|
 +
 +=== Useful Options for fdisk ===
 +
 +^Value^Description|
 +|d|Delete selected partition|
 +|p|Print partitions information|
 +|L|List available types of partitions|
 +
 +Don't forget to repeat the steps for all disks you using on the RAID.
 +
 +===== Creating a RAID 1 =====
 +<code>
 +
 +sudo mdadm --create /dev/md0 --level=mirror --raid-devices=2 /dev/sd[b-c]1
 +
 +</code>
 +
 +^Value^Description|
 +|–create|Create a new RAID|
 +|/dev/md0|Using /dev/md0|
 +|–level=mirror|Raid as Mirror|
 +|–raid-devices=2|Use 2 devices|
 +|/dev/sd[b-c]1|The devices sdb1 and sdc1|
 +
 +===== Creating File System on a RAID Device =====
 +
 +Use mkfs to create a ext4 File System with:
 +<code>
 +
 +sudo mkfs.ext4 /dev/md0
 +
 +</code>
 +===== Automount RAID on boot =====
 +
 +Edit your fstab to auto-mount your RAID on boot:
 +
 +<code>
 +sudo nano /etc/fstab
 +
 +</code>
 +
 +Eg:
 +
 +<code>
 +/dev/md0  /mnt/md0  ext4  defaults,nofail 0 0
 +
 +</code>
 +
 +To make sure that the array is reassembled automatically at boot, adjust your /etc/mdadm/mdadm.conf:
 +
 +<code>
 +sudo mdadm --detail --scan | sudo tee -a /etc/mdadm/mdadm.conf
 +
 +</code>
 +
 +Uncomment - if necessary - your array on /etc/mdadm/mdadm.conf by removing the Starting "#":
 +<code>
 +
 +sudo nano /etc/mdadm/mdadm.conf
 +
 +</code>
 +
 +Update the initramfs again so that the early boot process does not try to bring an unavailable array online:
 +
 +<code>
 +sudo update-initramfs -u
 +
 +</code>
 +
 +
 +===== Check Raid Status =====
 +
 +You can use the following commands to check the status of your RAID:
 +
 +<code>
 +sudo mdadm -E /dev/sd[b-c]1
 +
 +</code>
 +
 +<code>
 +sudo mdadm --detail /dev/md0
 +
 +</code>
 +
 +
 +