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How to Configure and Test RAID 1 on Ubuntu 20.4.1

To Configure and Test RAID 1 on Ubuntu 20.4.1

Introduction:

RAID (Redundant Array of Independent Disks) is a data storage virtualization technology that connects multiple physical disk drive components into one or more logical units for the purposes of data redundancy and performance improvement that was in contrast to the early concept of highly reliable mainframe disk drives referred to as "single large expensive disk". This video will cover the configuration process of Raid 1.

Configuration Procedure:

Check the OS version by using the below command:

root@linuxhelp:~# lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 20.04.1 LTS
Release:	20.04
Codename:	focal

Install Prerequisites by using the following command:

root@linuxhelp:~# apt-get install mdadm
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following additional packages will be installed:
  finalrd
Suggested packages:
  default-mta | mail-transport-agent dracut-core
The following NEW packages will be installed:
  finalrd mdadm
0 upgraded, 2 newly installed, 0 to remove and 277 not upgraded.
Need to get 424 kB of archives.
After this operation, 1,285 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 http://in.archive.ubuntu.com/ubuntu focal-updates/main amd64 finalrd all 6~ubuntu20.04.1 [6,852 B]
.
.
.

Check the disk whether there is already raid is configured or not:

root@linuxhelp:~# mdadm -E /dev/sd[b-c]
mdadm: No md superblock detected on /dev/sdb.
mdadm: No md superblock detected on /dev/sdc.

Drive partitioning for Raid:

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 0x4471dc9f.
**Press ‘n‘ for creating new partition.**
Command (m for help): n
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Then choose ‘P‘ for Primary partition.
Select (default p): p
Next select the partition number as 1.
Partition number (1-4, default 1): 1
Give the default full size by just pressing two times Enter key.
First sector (2048-41943039, default 2048): 
Last sector, +/-sectors or +/-size{K,M,G,T,P} (2048-41943039, default 41943039): 
Created a new partition 1 of type 'Linux' and of size 20 GiB.
Next press ‘p‘ to print the defined partition.
Command (m for help): p
Disk /dev/sdb: 20 GiB, 21474836480 bytes, 41943040 sectors
Disk model: VMware Virtual S
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x4471dc9f
Device     Boot Start      End  Sectors Size Id Type
/dev/sdb1        2048 41943039 41940992  20G 83 Linux
Press ‘L‘ to list all available types.
Command (m for help): l
 0  Empty           24  NEC DOS         81  Minix / old Lin bf  Solaris        
 1  FAT12           27  Hidden NTFS Win 82  Linux swap / So c1  DRDOS/sec (FAT-
 2  XENIX root      39  Plan 9          83  Linux           c4  DRDOS/sec (FAT-
 3  XENIX usr       3c  PartitionMagic  84  OS/2 hidden or  c6  DRDOS/sec (FAT-
 4  FAT16 <32M      40  Venix 80286     85  Linux extended  c7  Syrinx         
 5  Extended        41  PPC PReP Boot   86  NTFS volume set da  Non-FS data    
 6  FAT16           42  SFS             87  NTFS volume set db  CP/M / CTOS / .
 7  HPFS/NTFS/exFAT 4d  QNX4.x          88  Linux plaintext de  Dell Utility   
 8  AIX             4e  QNX4.x 2nd part 8e  Linux LVM       df  BootIt         
 9  AIX bootable    4f  QNX4.x 3rd part 93  Amoeba          e1  DOS access     
 a  OS/2 Boot Manag 50  OnTrack DM      94  Amoeba BBT      e3  DOS R/O        
 b  W95 FAT32       51  OnTrack DM6 Aux 9f  BSD/OS          e4  SpeedStor      
 c  W95 FAT32 (LBA) 52  CP/M            a0  IBM Thinkpad hi ea  Rufus alignment
 e  W95 FAT16 (LBA) 53  OnTrack DM6 Aux a5  FreeBSD         eb  BeOS fs        
 f  W95 Ext'd (LBA) 54  OnTrackDM6      a6  OpenBSD         ee  GPT            
10  OPUS            55  EZ-Drive        a7  NeXTSTEP        ef  EFI (FAT-12/16/
11  Hidden FAT12    56  Golden Bow      a8  Darwin UFS      f0  Linux/PA-RISC b
12  Compaq diagnost 5c  Priam Edisk     a9  NetBSD          f1  SpeedStor      
14  Hidden FAT16 <3 61  SpeedStor       ab  Darwin boot     f4  SpeedStor      
16  Hidden FAT16    63  GNU HURD or Sys af  HFS / HFS+      f2  DOS secondary  
17  Hidden HPFS/NTF 64  Novell Netware  b7  BSDI fs         fb  VMware VMFS    
18  AST SmartSleep  65  Novell Netware  b8  BSDI swap       fc  VMware VMKCORE 
1b  Hidden W95 FAT3 70  DiskSecure Mult bb  Boot Wizard hid fd  Linux raid auto
1c  Hidden W95 FAT3 75  PC/IX           bc  Acronis FAT32 L fe  LANstep        
1e  Hidden W95 FAT1 80  Old Minix       be  Solaris boot    ff  BBT            
Type ‘t‘to choose the partitions.
Command (m for help): t
Selected partition 1
Choose ‘fd‘ for Linux raid auto and press Enter to apply.
Hex code (type L to list all codes): fd
Changed type of partition 'Linux' to 'Linux raid autodetect'.
Then again use ‘p‘ to print the changes what we have made.
Command (m for help): p
Disk /dev/sdb: 20 GiB, 21474836480 bytes, 41943040 sectors
Disk model: VMware Virtual S
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x4471dc9f
Device     Boot Start      End  Sectors Size Id Type
/dev/sdb1        2048 41943039 41940992  20G fd Linux raid autodetect
Use ‘w‘ to write the changes.
Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

Create another disk :

root@linuxhelp:~# fdisk /dev/sdc
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 0xbc2a1a89.
Press ‘n‘ for creating new partition.
Command (m for help): n
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Then choose ‘P‘ for Primary partition.
Select (default p): p
Next select the partition number as 1.
Partition number (1-4, default 1): 1
Give the default full size by just pressing two times Enter key.
First sector (2048-41943039, default 2048): 
Last sector, +/-sectors or +/-size{K,M,G,T,P} (2048-41943039, default 41943039): 
Created a new partition 1 of type 'Linux' and of size 20 GiB.
Next press ‘p‘ to print the defined partition.
Command (m for help): p
Disk /dev/sdc: 20 GiB, 21474836480 bytes, 41943040 sectors
Disk model: VMware Virtual S
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xbc2a1a89
Device     Boot Start      End  Sectors Size Id Type
/dev/sdc1        2048 41943039 41940992  20G 83 Linux
Press ‘L‘ to list all available types.
Command (m for help): l
 0  Empty           24  NEC DOS         81  Minix / old Lin bf  Solaris        
 1  FAT12           27  Hidden NTFS Win 82  Linux swap / So c1  DRDOS/sec (FAT-
 2  XENIX root      39  Plan 9          83  Linux           c4  DRDOS/sec (FAT-
 3  XENIX usr       3c  PartitionMagic  84  OS/2 hidden or  c6  DRDOS/sec (FAT-
 4  FAT16 <32M      40  Venix 80286     85  Linux extended  c7  Syrinx         
 5  Extended        41  PPC PReP Boot   86  NTFS volume set da  Non-FS data    
 6  FAT16           42  SFS             87  NTFS volume set db  CP/M / CTOS / .
 7  HPFS/NTFS/exFAT 4d  QNX4.x          88  Linux plaintext de  Dell Utility   
 8  AIX             4e  QNX4.x 2nd part 8e  Linux LVM       df  BootIt         
 9  AIX bootable    4f  QNX4.x 3rd part 93  Amoeba          e1  DOS access     
 a  OS/2 Boot Manag 50  OnTrack DM      94  Amoeba BBT      e3  DOS R/O        
 b  W95 FAT32       51  OnTrack DM6 Aux 9f  BSD/OS          e4  SpeedStor      
 c  W95 FAT32 (LBA) 52  CP/M            a0  IBM Thinkpad hi ea  Rufus alignment
 e  W95 FAT16 (LBA) 53  OnTrack DM6 Aux a5  FreeBSD         eb  BeOS fs        
 f  W95 Ext'd (LBA) 54  OnTrackDM6      a6  OpenBSD         ee  GPT            
10  OPUS            55  EZ-Drive        a7  NeXTSTEP        ef  EFI (FAT-12/16/
11  Hidden FAT12    56  Golden Bow      a8  Darwin UFS      f0  Linux/PA-RISC b
12  Compaq diagnost 5c  Priam Edisk     a9  NetBSD          f1  SpeedStor      
14  Hidden FAT16 <3 61  SpeedStor       ab  Darwin boot     f4  SpeedStor      
16  Hidden FAT16    63  GNU HURD or Sys af  HFS / HFS+      f2  DOS secondary  
17  Hidden HPFS/NTF 64  Novell Netware  b7  BSDI fs         fb  VMware VMFS    
18  AST SmartSleep  65  Novell Netware  b8  BSDI swap       fc  VMware VMKCORE 
1b  Hidden W95 FAT3 70  DiskSecure Mult bb  Boot Wizard hid fd  Linux raid auto
1c  Hidden W95 FAT3 75  PC/IX           bc  Acronis FAT32 L fe  LANstep        
1e  Hidden W95 FAT1 80  Old Minix       be  Solaris boot    ff  BBT            
Type ‘t‘to choose the partitions.
Command (m for help): t
Selected partition 1
Choose ‘fd‘ for Linux raid auto and press Enter to apply.
Hex code (type L to list all codes): fd
Changed type of partition 'Linux' to 'Linux raid autodetect'.
Then again use ‘p‘ to print the changes what we have made.
Command (m for help): p
Disk /dev/sdc: 20 GiB, 21474836480 bytes, 41943040 sectors
Disk model: VMware Virtual S
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xbc2a1a89
Device     Boot Start      End  Sectors Size Id Type
/dev/sdc1        2048 41943039 41940992  20G fd Linux raid autodetect
Use ‘w‘ to write the changes.
Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

verify the changes on both drive using the same ‘mdadm‘ command:

root@linuxhelp:~# mdadm -E /dev/sd[b-c]
/dev/sdb:
   MBR Magic : aa55
Partition[0] :     41940992 sectors at         2048 (type fd)
/dev/sdc:
   MBR Magic : aa55
Partition[0] :     41940992 sectors at         2048 (type fd)

Create RAID 1 devices:

root@linuxhelp:~# mdadm -C /dev/md0 -l 1 -n 2 /dev/sd[b-c]1
mdadm: Note: this array has metadata at the start and
    may not be suitable as a boot device.  If you plan to
    store '/boot' on this device please ensure that
    your boot-loader understands md/v1.x metadata, or use
    --metadata=0.90
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.

Check the status of raid1 device:

root@linuxhelp:~# cat /proc/mdstat
Personalities : [raid1] 
md0 : active raid1 sdc1[1] sdb1[0]
      20953088 blocks super 1.2 [2/2] [UU]
      [=>...................]  resync =  7.6% (1606464/20953088) finish=4.8min speed=66936K/sec   
unused devices: <none>

Check the details of raid1 devices:

root@linuxhelp:~# mdadm --detail  /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Thu Jan 21 10:04:00 2021
        Raid Level : raid1
        Array Size : 20953088 (19.98 GiB 21.46 GB)
     Used Dev Size : 20953088 (19.98 GiB 21.46 GB)
      Raid Devices : 2
     Total Devices : 2
       Persistence : Superblock is persistent

       Update Time : Thu Jan 21 10:05:04 2021
             State : clean, resyncing 
    Active Devices : 2
   Working Devices : 2
    Failed Devices : 0
     Spare Devices : 0

Consistency Policy : resync

     Resync Status : 21% complete

              Name : linuxhelp:0  (local to host linuxhelp)
              UUID : 913406e8:c22d009a:9aaead9b:b808aae1
            Events : 3

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1

Create the File system on Raid device:

root@linuxhelp:~# mkfs.ext4 /dev/md0
mke2fs 1.45.5 (07-Jan-2020)
Creating filesystem with 5238272 4k blocks and 1310720 inodes
Filesystem UUID: 4f7aa4f9-f7e0-4ca4-8865-8a3e340fce73
Superblock backups stored on blocks: 
	32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
	4096000

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

Mount the newly created filesystem under ‘/mnt/raid1‘ and create some files and verify the contents under mount point.

root@linuxhelp:~# mkdir /mnt/raid1

root@linuxhelp:~# mount /dev/md0 /mnt/raid1

root@linuxhelp:~# touch /mnt/raid1/linux.txt
root@linuxhelp:~# echo "Welcome to linuxhelp" > /mnt/raid1/linux.txt

Check the status of raid1 device:

root@linuxhelp:~# cat /proc/mdstat
Personalities : [raid1] 
md0 : active raid1 sdc1[1] sdb1[0]
      20953088 blocks super 1.2 [2/2] [UU]
      
unused devices: <none>

Open “fstab” file and add the following line:

root@linuxhelp:~# vim /etc/fstab 
/dev/md0                /mnt/raid1              ext4    defaults        0 0

Check the details of raid1 devices:

root@linuxhelp:~# mdadm --detail /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Thu Jan 21 10:04:00 2021
        Raid Level : raid1
        Array Size : 20953088 (19.98 GiB 21.46 GB)
     Used Dev Size : 20953088 (19.98 GiB 21.46 GB)
      Raid Devices : 2
     Total Devices : 2
       Persistence : Superblock is persistent

       Update Time : Thu Jan 21 10:15:10 2021
             State : clean 
    Active Devices : 2
   Working Devices : 2
    Failed Devices : 0
     Spare Devices : 0

Consistency Policy : resync

              Name : linuxhelp:0  (local to host linuxhelp)
              UUID : 913406e8:c22d009a:9aaead9b:b808aae1
            Events : 21

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1

Before removing a disk we have to mark the disk as failed one, then only we can able to remove it. Remove the disk by using following command:

root@linuxhelp:~# mdadm -f /dev/md0 /dev/sdc1
mdadm: set /dev/sdc1 faulty in /dev/md0
check the details:
root@linuxhelp:~# mdadm --detail /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Thu Jan 21 10:04:00 2021
        Raid Level : raid1
        Array Size : 20953088 (19.98 GiB 21.46 GB)
     Used Dev Size : 20953088 (19.98 GiB 21.46 GB)
      Raid Devices : 2
     Total Devices : 2
       Persistence : Superblock is persistent

       Update Time : Thu Jan 21 10:17:42 2021
             State : clean, degraded 
    Active Devices : 1
   Working Devices : 1
    Failed Devices : 1
     Spare Devices : 0

Consistency Policy : resync

              Name : linuxhelp:0  (local to host linuxhelp)
              UUID : 913406e8:c22d009a:9aaead9b:b808aae1
            Events : 23

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       -       0        0        1      removed

       1       8       33        -      faulty   /dev/sdc1

Now, remove the disk “sdc1”:

root@linuxhelp:~# mdadm --remove /dev/md0 /dev/sdc1
mdadm: hot removed /dev/sdc1 from /dev/md0

check the details:

root@linuxhelp:~# mdadm --detail /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Thu Jan 21 10:04:00 2021
        Raid Level : raid1
        Array Size : 20953088 (19.98 GiB 21.46 GB)
     Used Dev Size : 20953088 (19.98 GiB 21.46 GB)
      Raid Devices : 2
     Total Devices : 1
       Persistence : Superblock is persistent

       Update Time : Thu Jan 21 10:18:34 2021
             State : clean, degraded 
    Active Devices : 1
   Working Devices : 1
    Failed Devices : 0
     Spare Devices : 0

Consistency Policy : resync

              Name : linuxhelp:0  (local to host linuxhelp)
              UUID : 913406e8:c22d009a:9aaead9b:b808aae1
            Events : 24

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       -       0        0        1      removed

Verify the data after disk failure:

root@linuxhelp:~# cd /mnt/raid1/
root@linuxhelp:/mnt/raid1# du -sh linux.txt 
4.0K	linux.txt

Now, add the disk to replace the failure disk:

root@linuxhelp:/mnt/raid1# mdadm --manage /dev/md0 --add /dev/sdc1
mdadm: added /dev/sdc1

check the details:

root@linuxhelp:/mnt/raid1# mdadm --detail /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Thu Jan 21 10:04:00 2021
        Raid Level : raid1
        Array Size : 20953088 (19.98 GiB 21.46 GB)
     Used Dev Size : 20953088 (19.98 GiB 21.46 GB)
      Raid Devices : 2
     Total Devices : 2
       Persistence : Superblock is persistent

       Update Time : Thu Jan 21 10:24:13 2021
             State : clean, degraded, recovering 
    Active Devices : 1
   Working Devices : 2
    Failed Devices : 0
     Spare Devices : 1

Consistency Policy : resync

    Rebuild Status : 21% complete

              Name : linuxhelp:0  (local to host linuxhelp)
              UUID : 913406e8:c22d009a:9aaead9b:b808aae1
            Events : 33

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       2       8       33        1      spare rebuilding   /dev/sdc1

With, this method configuration of raid 1 on Ubuntu comes to an end.

Tag : RAID Ubuntu
FAQ
Q
Which RAID is fastest?
A
RAID 0: RAID 0 is the only RAID type without fault tolerance. It is also by far the fastest RAID type. RAID 0 works by using striping, which disperses system data blocks across several different disks.
Q
Which RAID is safest?
A
Among the common RAID levels, there are two that are typically seen as the most secure.
This RAID configuration is considered the most common secure RAID level.
A RAID 6 configuration is very similar to RAID 5 except that it has parity data written on two drives.
Q
What Are the Types of RAID?
A
RAID 0 (Striping) RAID 0 is taking any number of disks and merging them into one large volume.
RAID 1 (Mirroring)
RAID 5/6 (Striping + Distributed Parity)
RAID 10 (Mirroring + Striping)
Software RAID.
Hardware RAID.
Q
How does RAID 1 work?
A
RAID 1 – This level is also called 'mirroring', which (as the name suggests) mirrors the same data across two disks - providing the lowest level of RAID redundancy. This level offers up to double the read performance over a single drive, but no increase in write speed
Q
What is a RAID?
A
RAID is a data storage virtualization technology that combines multiple physical disk drive components into one or more logical units for the purposes of data redundancy, performance improvement, or both. This was in contrast to the previous concept of highly reliable mainframe disk drives referred to as a single large expensive disk.