[Day1] (Super detailed steps) Build a soft RAID disk array

Table of Contents

First, build a disk array

(1) Install the mdadm tool

(2) Prepare for RAIDPartitions of the array

(3) Create RAID device

(4) Create and mount a file system (temporary mount)

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First add 4 SCSI hard disks to the linux server, use the mdadm software package to build a RAID5 disk array to improve the performance and reliability of disk storage.

First, build a disk array

(1) Install the mdadm tool

In the CentOS7.x system, the mdadm tool is provided by the mdadm-3.4-14.el7.x86_64 package. Execute the rpm-qa | grep mdadm command to check whether the mdadm tool is installed in the system.If the mdadm tool is not installed in the system, you can use RPM or YUM to install yum install mdadm -y

(2) Prepare partitions for RAID arrays

Add 4 SCSI hard drives to the Linux server.Use the fdisk tool to divide a 2GB partition, according to /dev/sdc1, /dev/sdd1, /dev/sde1, /dev/sdf1. (Because I have added a disk (sdb) before, and then add a disk tofrom sdc)

(How to add disk and disk partition in my previous blog)

(3) Create RAID device

Use the mdadm command to create a RAID, execute the following command to create a RAID5 named md0.

[[email protected] ~]# mdadm -Cv /dev/md0 -a yes -n4 -l5 /dev/sd[cdef]1

The functions of the parameters used in the above commands are as follows.

-C: Equivalent to create, which means new;

-v: Display the information during the creation process; /dev/md0: The name of the created RAID5;

-a: --auto, which means to inform mdadm whether to create a device file and assign an unused minor device number, followed by yes to automatically create a device file if it does not exist;

-n: Specify several hard disks to create RAID, n4 means use 4 hard disks to create RAID;

-l: Specify the RAID level, l5 means create RAID5; /dev/sd[bcde]1: Specify four disk partitions.View RAID5 creation results.

(4) Create and mount a file system (temporary mount)

[[email protected] ~]# mkfs -t xfs /dev/md0

[[email protected] ~]# mkdir /raidme

[[email protected] ~]# mount /dev/md0 /raidme/

[[email protected] ~]# df -hT

From the value in the result of the above df -hT command /dev/md0 has a capacity of 6G.4 pieces of 2G disk should be 8G, why the capacity only shows 6G?This is the characteristic of RAID5, and the part for storing parity data is not displayed.