• Mohammed Niyas

RHEL Storage, Partition & filesystem Type - Part 1

What is a Storage?


A storage in a linux is the hardware device connected to the VM/Hardware to handle the storage of data. For the purpose, we know a list device can be connected to the VM/Hardware running includes SATA disk, SSD, USB Memory etc.


What are Disk Partitions?

C, D, E Drives in your computer are the simple example to understand the disk partition. If you look at windows desktop my computer, you might a C, D etc drives. Similarly in linux, A partition is a section of storage drive but logically visible or can be treated as a separate device in operating system.


There are two type of partition format available.

MBR: Master Boot Record, is old and limited. It cannot be used for disks over 2 TB size and can have only 4 primary partition. For additional partition, logical partition inside a extended partition is being used.

GPT: is a solution for above limitation where no disk size limitaion.


How did you see the devices in Linux?


In RHEL, the naming scheme is file based, with file names in the form of /dev/xxyN

Let us have a look at the device naming,


/dev/ - This is the name of the directory in which all device files reside.

/dev/nvme0n1

As my device connected via NVME port and uses nvme driver in linux, my linux system boot partition show under nvme0n1.

dev/fd0 - The first floppy drive.

dev/fd1 - The second floppy drive.

dev/sda - The first SCSI disk SCSI ID address-wise.

dev/sdb - The second SCSI disk address-wise and so on.

dev/scd0 or /dev/sr0 - The first SCSI CD-ROM.

dev/hda - The primary disk on IDE primary controller.

dev/hdb - The secondary disk on IDE primary controller.

dev/mmcblk0 - SDHC card on PCMCIA. Special Device Naming.

dev/sdb - USB flash Drive against SCSI emulation.



[niyas@localhost home]$ lsblk
NAME          MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sr0            11:0    1 1024M  0 rom  
nvme0n1       259:0    0   40G  0 disk 
├─nvme0n1p1   259:1    0    1G  0 part /boot
└─nvme0n1p2   259:2    0   39G  0 part 
  ├─rhel-root 253:0    0 35.1G  0 lvm  /
  └─rhel-swap 253:1    0    4G  0 lvm  [SWAP]
nvme0n2       259:3    0    5G  0 disk 
└─nvme0n2p1   259:4    0 1023M  0 part /home/datafolder
nvme0n3       259:5    0    5G  0 disk 


Filesystem Type:

A filesystem is how data written to the disks are structured, With out a file system you cannot use the disk as part of the operating system. Example : NTFS in windows, FAT for USB, ext4 in linux.


How did you configure a file system for a disk?

Simple term is format and choose the right filesystem you need.


Let us see some of the most popular filesystems in linux:

Ext4: fourth version of extended filesystem. General filesystem if no specific requirment

XFS: if your requirement is for high performance, handling large files and live snapshot feature. The use XFS format.



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