LVM (Logical volume manager)

How to create LVM

Step by step:-

Fdisk -cu /dev/sda ----press Enter key

First Create a Extended partition

Next-- press P (to check partition table)

Next—press n (to create a new partition table)

Next –press E (to create Extended partition)

After that, here create two more partition for creating a pv.

Fdisk –cu /dev/sda

Then… press n for create a new partition

Then …put partition size what ever you want to give. Ex. ….+1G

Then …press t (to change partition id code)

Then..put the partition no. like (1-8):8 & press Enter key .

Then ..type LVM hex id code : 8e

Then …press W (to write a partition table. Save & exit)

Then…give a command partx -a /dev/sda (to inform the kernel about new partition tables)

Now, create a pv

Pvcreate /dev/sda5 /dev/sda6 (cross check command pvs or pvdisplay)

Now, create a vg

Vgcreate IT /dev/sda5 /dev/sda6 (cross check command vg or vgdisplay)

(IT :- give a volume groupname or u can give any name)

Now,create a LVM

lvcreate -L 1G –n LV IT ( logical volume created)(corss check lvs or lvdisplay)

Now, Format to lvm partition:-

Mkfs.ext4 /dev/IT/LV

Then ..create a mount point directory mkdir /lv

Now, mount to the partition mount /dev/IT/LV /lv/

df- hT (to check LVM partition)

now put permanent entries in /etc/fstab like that,

vim /etc/fstab

/dev/IT/LV /lv ext4 defaults 0 0

Mount -a (to check mounted or not , if not proper mount then it’s show some errors)

Then…lvs (for check mounting partition on lvm).

# how to Extend LVM.

• Lvextend -L 1.5G /dev/IT/LV
• Resize2fs /dev/IT/LV
• Lvs ( to check extend LVM)

# how to reduce LVM

• 1^st umount /lv
• E2fsck -f /dev/IT/LV (for scanning bad sector in hard disk)
• Resize2fs /dev/IT/LV 1G (mention lvm size how much space should I reduce)
• Lvreduce -L /dev/IT/LV then press “yes”
• Lvs (to check the lvm reduce command)
• Now, mount the directory again … mount /lv

# how to extend VG size (volume group)

• Fdisk -cu /dev/sda
• N (to create a new partition table)
• T(to change LVM partition id code 8e)
• W (write the partition tabled, save & exit)
• Partx –a /dev /sda (to inform the kernel)
• Now, pvcreate /dev/sda7 or some else
• Vgextend IT /dev/sda7 (IT stands for groupname)
• Vgdisplay (cross check vg extend or note)

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Incrypted partition (password protected partion)

# First entry

• Fdisk –cu /dev/sda
• P (print a partition table)
• N (create a new partition table)
• E (to create extend partition )
• Again create a new partition table
• W (to write table save & exit)
• Partx –a /dev/sda (to inform the kernel)
• Crypt setup luks Format /dev/sda5
• Then type “YES” put in uppercase letter.
• Asked for passwd phrase: ------(give passwd)
• Verify passwd phrase : ……….(again enter same passwd)
• Crypt setup luksOpen /dev/sda5 secure (“secure” stands for levels)
• Enter passwd phrase for /dev/sda5 : …… (passwd enter)
• Now, format the partition. mkfs.ext4 /dev/mapper/secure
• Then, create a mount point directory mkdir crypt or Parmendra
• Now, mount /dev/mapper/secure/crypt
• Then, put entries in vim /etc/fstab
• /dev/mapper/secure /crypt ext4 defaults 0 0

# now, Second entry

• Vim /etc/crypt

Secure /dev/sda5 (Actual device & level entries)

# Normal using LUKS

• Umount /crypt
• Cryptsetup luksClose /dev/mapper/sercure
• Then, Format the drive mkfs.ext4 /dev/sda5
• Vim /etc/crypttab

/dev/sda5 /crypt ext4 defaults 0 0

• Then , mount -a (to check the mount point)