Understanding of RAID
RAID 0
RAID 1
RAID 2
RAID 5 (distributed read-write and parity calculation)
RAID 6 (distributed read-write and parity information)
RAID comparison
MDADM
Create raid 0
1. Add 4 hard disks (custom size)
2. Create raid 0 (after successful creation, the following message is displayed as success)
-C: create a new RAID
-a: automatically create the corresponding device
-l specify the RAID level to be created
-n: Specify the number of hard disks
/dev/md0: path
/dev/sdb and /dev/sdc: two devices
0: raid level
3. View the detailed information of the created disk: madam -D /dev/md0
4. Create A configuration file makes the created raid take effect permanently:
3. Create a file system for permanent mounting:
a. Format the file system with md0 as ext4: mkfs -t ext4 /dev/md0
b. Create a mount point: mkdir /mnt/ raid0
c. Mount: mount /dev/md0/ /mnt/raid0/
d. View: df -hT
e. Copy the file (pay attention to the path):
4. Modify the fstab file (the last line is the added information section to achieve permanent mounting Upload):
vim /etc/fstab
Create and backup disks of other raid levels
Control RAID
1. Uninstall and then close (this operation restart will also start raid):
umount /dev/md0
madam -S /dev/md0
2. Clear the RAID information on the underlying disk of the RAID
mdadm --zero-superblock /dev/sdb
Creation of RAID 5 (use one of the hard drives as backup hard drives at the same time)
1. Create and backup disk
2. View detailed information: mdadm -D /dev/md0
Simulated failure
