System Foundations - Linux RAID

Опубликовано: 16 Октябрь 2024
на канале: The Expat Professor

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Lab 0x05 - Linux RAID

Overview
This lab will guide the student through creating a RAID array from image files created within a virtual machine. These principles translate directly to creating an array using physical devices. sudo -s is recommended as nearly all of the commands will require root-level/superuser access privileges.

Requirements
Linux Physical or Virtual Machine

Part 1 - Create and Allocate the Disk Image Files
for num in 0 1 2 3 4; do dd if=/dev/zero of=./disk$num.img bs=1M count=1024; done

for num in 0 1 2 3 4; do losetup -f disk$num.img; done

losetup -l

Part 2 - Create and Verify the RAID Array

mdadm --create --verbose /dev/md0 --level=5 --raid-devices=5 /dev/loop{0..4}

/dev/loop1 /dev/loop2 /dev/loop3 /dev/loop4
mdadm --detail /dev/md0

Part 3 - Format and Mount the Array
Make the partition
parted /dev/md0 mklabel msdos
parted /dev/md0 mkpart primary ext2 0% 100%

Format the partition
mkfs.ext4 -L RAID00 /dev/md0p1

Mount the partition
mount /dev/md0p1 /mnt

Copy files to the partition
ll /mnt/
cp /etc/* /mnt/
ll /mnt/

Check the Size and Details of the Array
lsblk
df -h

Part 4 - Cause a Drive Failure
Unmount the array
umount /mnt
ll /mnt/

Stop the array
mdadm --stop /dev/md0

Delete a disk image
rm -f disk3.img

Remove the loopback
losetup -d /dev/loop3

Start the array without a drive
mdadm --assemble /dev/md0 --verbose --force /dev/loop{0,1,2,4}

Optional (before restarting array)
Mark the Drive as "failed"
mdadm /dev/md0 --fail /dev/loop3

Remove the failed drive
mdadm /dev/md0 --remove /dev/loop3

Check the array status
mdadm --detail /dev/md0

Mount the partition
mount /dev/md0p1 /mnt

Verify the Contents
ll /mnt/

Part 5 - Repair the Array
Recreate and Add disk3.img
dd if=/dev/zero of=./disk3.img bs=1M count=1024
losetup /dev/loop3 disk3.img
mdadm /dev/md0 --add /dev/loop3

Verify that the Array is rebuilding
mdadm --detail /dev/md0
It may take about 80 seconds for the array to rebuild

Part 6 - Remove the Array
mdadm --detail /dev/md0
umount /mnt
ll /mnt/
mdadm --stop /dev/md0
mdadm --remove /dev/md0 #(if present)
losetup -D
mdadm --examine --scan

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