Learn linux disk space allocation

fdisk shows the disk partition distribution

fdisk to list partition

In below example, user has created two partitions on disk /dev/xvda

1. Primary with /dev/xvda1 name and size 487M

2. Extended with /dev/xvda2 name and size 149.5G

Also, Extended partition is mapped for Linux LVM here with name /dev/xvda5

root@ubuntu-231:~# fdisk -l

Disk /dev/xvda: 150 GiB, 161061273600 bytes, 314572800 sectors

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: 0x4b63a199

Device Boot Start End Sectors Size Id Type

/dev/xvda1 2048 999423 997376 487M 83 Linux

/dev/xvda2 1001470 314570751 313569282 149.5G 5 Extended

/dev/xvda5 1001472 314570751 313569280 149.5G 8e Linux LVM

Disk /dev/mapper/ubuntu--vg-root: 145.4 GiB, 156074246144 bytes, 304832512 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/mapper/ubuntu--vg-swap_1: 4.1 GiB, 4420796416 bytes, 8634368 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

root@ubuntu-231:~# cat /etc/fstab

# /etc/fstab: static file system information.

Map fdisk output with /etc/fstab

mapping of partition to disk folder path

In below example, LVM partition is mounted to / in the linux

root@ubuntu-231:~# df -h | grep ubuntu--vg-root

/dev/mapper/ubuntu--vg-root 143G 65G 72G 48%

root@ubuntu-231:~# cat /etc/fstab

# /etc/fstab: static file system information.

#

# Use 'blkid' to print the universally unique identifier for a

# device; this may be used with UUID= as a more robust way to name devices

# that works even if disks are added and removed. See fstab(5).

#

# <file system> <mount point> <type> <options> <dump> <pass>

/dev/mapper/ubuntu--vg-root / ext4 errors=remount-ro 0 1

# /boot was on /dev/xvda1 during installation

UUID=974a3323-e9f2-407b-9280-2b81b36dd55c /boot ext2 defaults 0 2

#/dev/mapper/ubuntu--vg-swap_1 none swap sw 0 0

Reference

Discussion with IT team

Personal try

https://www.howtogeek.com/106873/how-to-use-fdisk-to-manage-partitions-on-linux/