How to Configure and Test Raid 10 On RedHat 7.6

How to configure and test Raid 10 on RedHat 7.6

Introduction:

RAID 10, also known as RAID 1+0, is a RAID configuration that combines disk mirroring and disk striping to protect data that requires the least number of four disks and stripes data across mirrored pairs. This tutorial will explain Raid 10 Configuration and testing on Redhat 7.6.

Configuration Process:

First and foremost check the disk details

root@linuxhelp:~# lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda      8:0    0   20G  0 disk 
├─sda1   8:1    0  3.7G  0 part /swap
├─sda2   8:2    0    1K  0 part 
├─sda5   8:5    0  976M  0 part /boot
└─sda6   8:6    0 15.3G  0 part /
sdb      8:16   0   20G  0 disk 
sdc      8:32   0   20G  0 disk 
sdd      8:48   0    2G  0 disk 
sde      8:64   0    2G  0 disk 
sdf      8:80   0    2G  0 disk 
sr0     11:0    1  1.9G  0 rom  

Now I will create partition of SDB, SDC, SDD, SDE,SDF disk by executing the following command

root@linuxhelp:~# fdisk /dev/sdb
Welcome to fdisk (util-linux 2.34).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0x4348c9fd.
Press n to create partition
Command (m for help): n
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Press p to choose the partition type
Select (default p): p
Partition number (1-4, default 1): 
First sector (2048-41943039, default 2048): 
Enter the size of the partition
Last sector, +/-sectors or +/-size{K,M,G,T,P} (2048-41943039, default 41943039): +1G
Created a new partition 1 of type 'Linux' and of size 1 GiB.
Press t to change the partition code
Command (m for help): t
Selected partition 1
Hex code (type L to list all codes): fd
Changed type of partition 'Linux' to 'Linux raid autodetect'.
Press w to write the partition
Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

I will follow the same process to create partition to other drives

root@linuxhelp:~# fdisk /dev/sdc 
Welcome to fdisk (util-linux 2.34).
Changes will remain in memory only, until you decide to write them.
.
.
.
Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

root@linuxhelp:~# fdisk /dev/sdd 
Welcome to fdisk (util-linux 2.34).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
.
.
.
Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

root@linuxhelp:~# fdisk /dev/sde 
Welcome to fdisk (util-linux 2.34).
Changes will remain in memory only, until you decide to write them.
.
.
.
Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

root@linuxhelp:~# fdisk /dev/sdf 
Welcome to fdisk (util-linux 2.34).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
.
.
.
Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

After the partition is created then list the disk If the partition is created or not

root@linuxhelp:~# lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda      8:0    0   20G  0 disk 
├─sda1   8:1    0  3.7G  0 part /swap
├─sda2   8:2    0    1K  0 part 
├─sda5   8:5    0  976M  0 part /boot
└─sda6   8:6    0 15.3G  0 part /
sdb      8:16   0   20G  0 disk 
└─sdb1   8:17   0    1G  0 part 
sdc      8:32   0   20G  0 disk 
└─sdc1   8:33   0    1G  0 part 
sdd      8:48   0    2G  0 disk 
└─sdd1   8:49   0    1G  0 part 
sde      8:64   0    2G  0 disk 
└─sde1   8:65   0    1G  0 part 
sdf      8:80   0    2G  0 disk 
└─sdf1   8:81   0    1G  0 part 
sr0     11:0    1  1.9G  0 rom  

After the partition is created then Create RAID using those partitions

root@linuxhelp:~# mdadm -C /dev/md0 -l 10 -n 4 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.

After RAID created now format the raid to ext4 file system

root@linuxhelp:~# mkfs.ext4 /dev/md0
mke2fs 1.45.5 (07-Jan-2020)
Creating filesystem with 523264 4k blocks and 130816 inodes
Filesystem UUID: d24481bd-1966-4151-a056-094ac82115ab
Superblock backups stored on blocks: 
	32768, 98304, 163840, 229376, 294912
Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done

Now check the details about RAID6

root@linuxhelp:~# mdadm --detail /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Thu Jan 22 7:50:08 2021
        Raid Level : raid10
        Array Size : 2093056 (2044.00 MiB 2143.29 MB)
     Used Dev Size : 1046528 (1022.00 MiB 1071.64 MB)
      Raid Devices : 4
     Total Devices : 4
       Persistence : Superblock is persistent
       Update Time : Thu Jan 22 07:53:09 2021
             State : clean 
    Active Devices : 4
   Working Devices : 4
    Failed Devices : 0
     Spare Devices : 0
            Layout : left-symmetric
        Chunk Size : 512K
Consistency Policy : resync
              Name : linuxhelp:0  (local to host linuxhelp)
              UUID : 99e1980b:6f9f682f:c3cda362:1c608272
            Events : 17
    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1
       2       8       49        2      active sync   /dev/sdd1
       3       8       65        3      active sync   /dev/sde1

Now create a directory for mount the raid by executing the following command

root@linuxhelp:~# mkdir data

After the directory is created now mount the raid to the directory

root@linuxhelp:~# mount /dev/md0 data/

Now list the disk if the raid is mounted or not

root@linuxhelp:~# df -h
Filesystem      Size  Used Avail Use% Mounted on
udev            1.9G     0  1.9G   0% /dev
tmpfs           391M  1.7M  390M   1% /run
/dev/sda6        16G  6.8G  7.5G  48% /
tmpfs           2.0G     0  2.0G   0% /dev/shm
tmpfs           5.0M  4.0K  5.0M   1% /run/lock
tmpfs           2.0G     0  2.0G   0% /sys/fs/cgroup
/dev/sda5       945M  108M  773M  13% /boot
/dev/sda1       3.7G   15M  3.4G   1% /swap
tmpfs           391M   16K  391M   1% /run/user/1000
/dev/md0        2.0G  6.0M  1.9G   1% /root/data

After the raid is mounted. Add some files to the data directory for test the raid 6

root@linuxhelp:~# cd data/
root@linuxhelp:~/data# touch linuxhelp.txt

Now edit the file by using vim editor

root@linuxhelp:~/data# vim linuxhelp.txt 

Now list the directory

root@linuxhelp:~/data# ls -la
total 28
drwxr-xr-x 3 root root  4096 Jan 21 11:56 .
drwx------ 5 root root  4096 Jan 21 11:56 ..
-rw-r--r-- 1 root root    21 Jan 21 11:56 linuxhelp.txt
drwx------ 2 root root 16384 Jan 21 11:53 lost+found

Now I will fail the any one drives from the Raid 10

root@linuxhelp:~/data# mdadm /dev/md0 -f /dev/sdb1
mdadm: set /dev/sdb1 faulty in /dev/md0
mdadm: set /dev/sdd1 faulty in /dev/md0

After that check the details of raid 10 if the drives are failed are not

root@linuxhelp:~/data# mdadm --detail /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Thu Jan 21 11:50:08 2021
        Raid Level : raid6
        Array Size : 2093056 (2044.00 MiB 2143.29 MB)
     Used Dev Size : 1046528 (1022.00 MiB 1071.64 MB)
      Raid Devices : 4
     Total Devices : 4
       Persistence : Superblock is persistent
       Update Time : Thu Jan 21 12:11:28 2021
             State : clean, degraded 
    Active Devices : 3
   Working Devices : 3
    Failed Devices : 1
     Spare Devices : 0
            Layout : left-symmetric
        Chunk Size : 512K
Consistency Policy : resync
              Name : linuxhelp:0  (local to host linuxhelp)
              UUID : 99e1980b:6f9f682f:c3cda362:1c608272
            Events : 21
    Number   Major   Minor   RaidDevice State
       -       0        0        0      removed
       1       8       33        1      active sync   /dev/sdc1
       -       0        0        2      removed
       3       8       65        3      active sync   /dev/sde1
       0       8       17        -      faulty   /dev/sdb1
       2       8       49        -      active   /dev/sdd1

After the drive is failed now remove those failed drives from the raid 6

root@linuxhelp:~/data# mdadm /dev/md0 -r /dev/sdb1 /dev/sdd1
mdadm: hot removed /dev/sdb1 from /dev/md0
mdadm: hot removed /dev/sdd1 from /dev/md0

Now list the disk by using the following command

root@linuxhelp:~/data# lsblk
NAME    MAJ:MIN RM  SIZE RO TYPE  MOUNTPOINT
sda       8:0    0   20G  0 disk  
├─sda1    8:1    0  3.7G  0 part  /swap
├─sda2    8:2    0    1K  0 part  
├─sda5    8:5    0  976M  0 part  /boot
└─sda6    8:6    0 15.3G  0 part  /
sdb       8:16   0   20G  0 disk  
└─sdb1    8:17   0    1G  0 part  
sdc       8:32   0   20G  0 disk  
└─sdc1    8:33   0    1G  0 part  
  └─md0   9:0    0    2G  0 raid6 /root/data
sdd       8:48   0    2G  0 disk  
└─sdd1    8:49   0    1G  0 part  
sde       8:64   0    2G  0 disk  
└─sde1    8:65   0    1G  0 part  
  └─md0   9:0    0    2G  0 raid6 /root/data
sdf       8:80   0    2G  0 disk  
└─sdf1    8:81   0    1G  0 part  
sr0      11:0    1  1.9G  0 rom 

Now add one new drives to the raid 10 by executing the following command

root@linuxhelp:~/data# mdadm /dev/md0 --add /dev/sdf1
mdadm: added /dev/sdf1

Now check the details about raid if the drive is added or not

root@linuxhelp:~/data# mdadm --detail /dev/md0 
/dev/md0:
           Version : 1.2
     Creation Time : Thu Jan 21 11:50:08 2021
        Raid Level : raid6
        Array Size : 2093056 (2044.00 MiB 2143.29 MB)
     Used Dev Size : 1046528 (1022.00 MiB 1071.64 MB)
      Raid Devices : 4
     Total Devices : 4
       Persistence : Superblock is persistent
       Update Time : Thu Jan 21 12:14:11 2021
             State : clean 
    Active Devices : 4
   Working Devices : 4
    Failed Devices : 0
     Spare Devices : 0
            Layout : left-symmetric
        Chunk Size : 512K
Consistency Policy : resync
              Name : linuxhelp:0  (local to host linuxhelp)
              UUID : 99e1980b:6f9f682f:c3cda362:1c608272
            Events : 43
    Number   Major   Minor   RaidDevice State
       1       8       33        1      active sync   /dev/sdc1
       4       8       81        2      active sync   /dev/sdf1
       3       8       65        3      active sync   /dev/sde1

Now check the raid directory if the data are stored or corrupted

root@linuxhelp:~/data# ls -la
total 28
drwxr-xr-x 3 root root  4096 Jan 21 11:56 .
drwx------ 5 root root  4096 Jan 21 11:56 ..
-rw-r--r-- 1 root root    21 Jan 21 11:56 linuxhelp.txt
drwx------ 2 root root 16384 Jan 21 11:53 lost+found

Now check the disk if the drives are mounted or not

root@linuxhelp:~/data# lsblk
NAME    MAJ:MIN RM  SIZE RO TYPE  MOUNTPOINT
sda       8:0    0   20G  0 disk  
├─sda1    8:1    0  3.7G  0 part  /swap
├─sda2    8:2    0    1K  0 part  
├─sda5    8:5    0  976M  0 part  /boot
└─sda6    8:6    0 15.3G  0 part  /
sdb       8:16   0   20G  0 disk  
└─sdb1    8:17   0    1G  0 part  
sdc       8:32   0   20G  0 disk  
└─sdc1    8:33   0    1G  0 part  
  └─md0   9:0    0    2G  0 raid6 /root/data
sdd       8:48   0    2G  0 disk  
└─sdd1    8:49   0    1G  0 part  
sde       8:64   0    2G  0 disk  
└─sde1    8:65   0    1G  0 part  
  └─md0   9:0    0    2G  0 raid6 /root/data
sdf       8:80   0    2G  0 disk  
└─sdf1    8:81   0    1G  0 part  
  └─md0   9:0    0    2G  0 raid6 /root/data
sr0      11:0    1  1.9G  0 rom   

With this method, the Configuration and Test RAID 10 on Redhat 7.6 is comes to an end.