RAID



AIM

                 To create a redundant array of inexpensive disk.
PROCEDURE
Step 1: Start the process by opening the terminal.
Step 2: List out all the disks available in the system using the command:
fdisk –l
Step 3: Make two partitions using the following command:
fdisk /dev/hdc
Step 4: Assign the raid hexa decimal code for the partitions.
Step 5: Again use the fdisk -l command to check whether the hexa decimal codes are assigned.
Step 6: Create the raid using the following command:
mdadm -C /dev/md0 -l 0 -n 2 /dev/hdc10 /dev/hdc11
Step 7: Format the disk using the command:
mkfs -t ext3 /dev/md0
Step 8: Mount the disk using the command:
mount /dev/md0 /mnt
Step 9: Use the following command to unmount the disk:
cd /mnt
Step10: Use the df command to view the disk space.
Step11: Make the copy of the data from one disk to another disk using the command:
cp -r /dev/hdc10 /dev/hdc11 /mnt
Step12: Unmount the disks and use the below command to stop the md0:
mdadm --stop /dev/md0
Step13: Finally remove md0 by using the following command:
mdadm --remove /dev/md0
Step14: Delete the created partitions using the fdisk /dev/hdc command .
Step15: Stop the process.


COMMANDS

1) List the disks
[root@lab15-33 ~]# fdisk -l

Disk /dev/hdc: 40.0 GB, 40020664320 bytes
255 heads, 63 sectors/track, 4865 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hdc1   *           1        1275    10241406   83  Linux
/dev/hdc2            1276        2550    10241437+  83  Linux
/dev/hdc3            2551        3825    10241437+  83  Linux
/dev/hdc4            3826        4865     8353800    5  Extended
/dev/hdc5            3826        4718     7172991   83  Linux
/dev/hdc6            4719        4730       96358+  83  Linux
/dev/hdc7            4731        4831      811251   83  Linux
/dev/hdc8            4832        4837       48163+  fd  Linux raid autodetect
/dev/hdc9            4838        4841       32098+  fd  Linux raid autodetect

2) Making disk partitions
[root@lab15-33 ~]# fdisk /dev/hdc

The number of cylinders for this disk is set to 4865.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): n
First cylinder (4842-4865, default 4842): 4842
Last cylinder or +size or +sizeM or +sizeK (4842-4865, default 4865): +5

Command (m for help): n
First cylinder (4848-4865, default 4848): 4848
Last cylinder or +size or +sizeM or +sizeK (4848-4865, default 4865): +5

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.
[root@lab15-33 ~]# partprobe

3) Assigning raid hexa decimal code
[root@lab15-33 ~]# fdisk /dev/hdc

The number of cylinders for this disk is set to 4865.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): t
Partition number (1-11): 11
Hex code (type L to list codes): l

 0  Empty           1c  Hidden W95 FAT3 70  DiskSecure Mult bb  Boot Wizard hid
 1  FAT12           1e  Hidden W95 FAT1 75  PC/IX           be  Solaris boot
 2  XENIX root      24  NEC DOS         80  Old Minix       c1  DRDOS/sec (FAT-
 3  XENIX usr       39  Plan 9          81  Minix / old Lin c4  DRDOS/sec (FAT-
 4  FAT16 <32M      3c  PartitionMagic  82  Linux swap      c6  DRDOS/sec (FAT-
 5  Extended        40  Venix 80286     83  Linux           c7  Syrinx
 6  FAT16           41  PPC PReP Boot   84  OS/2 hidden C:  da  Non-FS data
 7  HPFS/NTFS       42  SFS             85  Linux extended  db  CP/M / CTOS / .
 8  AIX             4d  QNX4.x          86  NTFS volume set de  Dell Utility
 9  AIX bootable    4e  QNX4.x 2nd part 87  NTFS volume set df  BootIt
 a  OS/2 Boot Manag 4f  QNX4.x 3rd part 8e  Linux LVM       e1  DOS access
 b  W95 FAT32       50  OnTrack DM      93  Amoeba          e3  DOS R/O
 c  W95 FAT32 (LBA) 51  OnTrack DM6 Aux 94  Amoeba BBT      e4  SpeedStor
 e  W95 FAT16 (LBA) 52  CP/M            9f  BSD/OS          eb  BeOS fs
 f  W95 Ext'd (LBA) 53  OnTrack DM6 Aux a0  IBM Thinkpad hi ee  EFI GPT
10  OPUS            54  OnTrackDM6      a5  FreeBSD         ef  EFI (FAT-12/16/
11  Hidden FAT12    55  EZ-Drive        a6  OpenBSD         f0  Linux/PA-RISC b
12  Compaq diagnost 56  Golden Bow      a7  NeXTSTEP        f1  SpeedStor
14  Hidden FAT16 <3 5c  Priam Edisk     a8  Darwin UFS      f4  SpeedStor
16  Hidden FAT16    61  SpeedStor       a9  NetBSD          f2  DOS secondary
17  Hidden HPFS/NTF 63  GNU HURD or Sys ab  Darwin boot     fd  Linux raid auto
18  AST SmartSleep  64  Novell Netware  b7  BSDI fs         fe  LANstep
1b  Hidden W95 FAT3 65  Novell Netware  b8  BSDI swap       ff  BBT
Hex code (type L to list codes): fd
Changed system type of partition 11 to fd (Linux raid autodetect)

Command (m for help): t
Partition number (1-11): 10
Hex code (type L to list codes): l

 0  Empty           1c  Hidden W95 FAT3 70  DiskSecure Mult bb  Boot Wizard hid
 1  FAT12           1e  Hidden W95 FAT1 75  PC/IX           be  Solaris boot
 2  XENIX root      24  NEC DOS         80  Old Minix       c1  DRDOS/sec (FAT-
 3  XENIX usr       39  Plan 9          81  Minix / old Lin c4  DRDOS/sec (FAT-
 4  FAT16 <32M      3c  PartitionMagic  82  Linux swap      c6  DRDOS/sec (FAT-
 5  Extended        40  Venix 80286     83  Linux           c7  Syrinx
 6  FAT16           41  PPC PReP Boot   84  OS/2 hidden C:  da  Non-FS data
 7  HPFS/NTFS       42  SFS             85  Linux extended  db  CP/M / CTOS / .
 8  AIX             4d  QNX4.x          86  NTFS volume set de  Dell Utility
 9  AIX bootable    4e  QNX4.x 2nd part 87  NTFS volume set df  BootIt
 a  OS/2 Boot Manag 4f  QNX4.x 3rd part 8e  Linux LVM       e1  DOS access
 b  W95 FAT32       50  OnTrack DM      93  Amoeba          e3  DOS R/O
 c  W95 FAT32 (LBA) 51  OnTrack DM6 Aux 94  Amoeba BBT      e4  SpeedStor
 e  W95 FAT16 (LBA) 52  CP/M            9f  BSD/OS          eb  BeOS fs
 f  W95 Ext'd (LBA) 53  OnTrack DM6 Aux a0  IBM Thinkpad hi ee  EFI GPT
10  OPUS            54  OnTrackDM6      a5  FreeBSD         ef  EFI (FAT-12/16/
11  Hidden FAT12    55  EZ-Drive        a6  OpenBSD         f0  Linux/PA-RISC b
12  Compaq diagnost 56  Golden Bow      a7  NeXTSTEP        f1  SpeedStor
14  Hidden FAT16 <3 5c  Priam Edisk     a8  Darwin UFS      f4  SpeedStor
16  Hidden FAT16    61  SpeedStor       a9  NetBSD          f2  DOS secondary
17  Hidden HPFS/NTF 63  GNU HURD or Sys ab  Darwin boot     fd  Linux raid auto
18  AST SmartSleep  64  Novell Netware  b7  BSDI fs         fe  LANstep
1b  Hidden W95 FAT3 65  Novell Netware  b8  BSDI swap       ff  BBT
Hex code (type L to list codes): fd
Changed system type of partition 10 to fd (Linux raid autodetect)

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.
[root@lab15-33 ~]# partprobe

4) Check for the assigned hexa decimal code
[root@lab15-33 ~]# fdisk -l

Disk /dev/hdc: 40.0 GB, 40020664320 bytes
255 heads, 63 sectors/track, 4865 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hdc1   *           1        1275    10241406   83  Linux
/dev/hdc2            1276        2550    10241437+  83  Linux
/dev/hdc3            2551        3825    10241437+  83  Linux
/dev/hdc4            3826        4865     8353800    5  Extended
/dev/hdc5            3826        4718     7172991   83  Linux
/dev/hdc6            4719        4730       96358+  83  Linux
/dev/hdc7            4731        4831      811251   83  Linux
/dev/hdc8            4832        4837       48163+  fd  Linux raid autodetect
/dev/hdc9            4838        4841       32098+  fd  Linux raid autodetect
/dev/hdc10           4842        4847       48163+  fd  Linux raid autodetect
/dev/hdc11           4848        4853       48163+  fd  Linux raid autodetect


5) Creating raid
[root@lab15-33 ~]# mdadm -C /dev/md0 -l 0 -n 2 /dev/hdc10 /dev/hdc11
mdadm: array /dev/md0 started.

6) Displaying partition numbers
[root@lab15-33 ~]# cat /proc/mdstat
Personalities : [raid0]
md0 : active raid0 hdc11[1] hdc10[0]
      96128 blocks 64k chunks

unused devices: <none>
[root@lab15-33 ~]# mkfs -t ext3 /dev/md0
mke2fs 1.35 (28-Feb-2004)
max_blocks 98435072, rsv_groups = 12016, rsv_gdb = 256
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
24096 inodes, 96128 blocks
4806 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=67371008
12 block groups
8192 blocks per group, 8192 fragments per group
2008 inodes per group
Superblock backups stored on blocks:
        8193, 24577, 40961, 57345, 73729

Writing inode tables: done
inode.i_blocks = 3074, i_size = 67383296
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 20 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.

7) Mounting the disks
[root@lab15-33 ~]# mount /dev/md0 /mnt

8) Unmounting the disks
[root@lab15-33 ~]# cd /mnt

9) Showing the disk space
[root@lab15-33 mnt]# df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/hdc3             10080520   6188712   3379740  65% /
/dev/hdc1             10080488     58280   9510140   1% /boot
none                    253996         0    253996   0% /dev/shm
/dev/hdc2             10080520     56472   9511980   1% /home
/dev/hdc5              7060276    191180   6510448   3% /var
/dev/md0                 93079      5664     82609   7% /mnt

10) Mirroring
[root@lab15-33 mnt]# cp -r /dev/hdc10 /dev/hdc11 /mnt

11) List out the partitions
[root@lab15-33 mnt]# ls
hdc10  hdc11  lost+found

12) Coming out of the mount directory
[root@lab15-33 mnt]# cd ..

13) Mounting
[root@lab15-33 /]# umount /mnt

14) Stopping the md0
[root@lab15-33 /]# mdadm --stop /dev/md0

15) Removing the md0
[root@lab15-33 /]# mdadm --remove /dev/md0

16) Deleting the created partitions
[root@lab15-33 /]# fdisk /dev/hdc

The number of cylinders for this disk is set to 4865.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): d
Partition number (1-11): 10

Command (m for help): d
Partition number (1-10): 11
Value out of range.
Partition number (1-10): 9

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.

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