CentOS /Linux: How To Mount Read-only File System

Mount command mainly use to mount the file system or hardware disk such as: CD-ROM, portable hard driver and Flash disk that were found by CentOS Linux System or other Linux distribution version. How do I mount a Ext3 or Ext4 file system under Linux system or CentOS operating system? How to mount a read only ext3 file system under linux system? In this post you ‘ll see the way to mount read only file system using linux mount command.

CentOS Linux Mounting Ext3 File System

Assuming that there is a ext3 file system under /dev/sdb1 partition, you must mount it  to a directory so that it is availabe to use. type the following command to mount this file system to /mnt/disk directory, type:

$mount -t ext3 /dev/sdb1 /mnt/disk

If you want this file system to be mounted automatically while system starts up, need to define mouting relationship in /etc/fstab configuration file, using “vim” command to edit /etc/fstab file and adding  the below content:

/dev/sdb1                   /mnt/disk                    ext3   defaults        0 0

Then you can directly use the below simple command to mount  that ext3 filesystem.

$mount  /mnt/disk

CentOS Linux Mounting Read Only File System

Mounting a read only file system need to use “-o ” option and providing “ro” value for option, issue the following command to mount read only filesystem under /dev/sdb1 partition, type:

$sudo mount -t ext3 -o ro  /dev/sdb1 /mnt/disk

How to change a mounted filesystem as  read only mode?

If you have mounted a file system using mount command and wanna to change it to read only, issue the following command:

$sudo mount -o remount,ro /mnt/disk