Book Image

Ubuntu 20.04 Essentials

By : Neil Smyth
Book Image

Ubuntu 20.04 Essentials

By: Neil Smyth

Overview of this book

Ubuntu is undeniably one of the most highly regarded and widely used Debian-based Linux distributions available today. Thanks to its ease of use and reliability, Ubuntu has a loyal following of Linux users and an active community of developers. Ubuntu 20.04 Essentials is designed to take you through the installation, use, and administration of the Ubuntu 20.04 distribution in detail. For beginners, the book covers topics such as operating system installation, the basics of the GNOME desktop environment, configuring email and web servers, and installing packages and system updates. Additional installation topics such as dual booting with Microsoft Windows are also covered along with crucial security topics such as configuring a firewall and user and group administration. For the experienced user, the book delves into topics such as remote desktop access, the Cockpit web interface, logical volume management (LVM), disk partitioning, and swap management. Further, it also explores KVM virtualization, Secure Shell (SSH), Linux containers, and file sharing using both Samba and NFS to provide a thorough overview of this enterprise-class operating system.
Table of Contents (38 chapters)
38
Index

34.5 An Overview of Journaled File Systems

A journaling filesystem keeps a journal or log of the changes that are being made to the filesystem during disk writing that can be used to rapidly reconstruct corruptions that may occur due to events such as a system crash or power outage.

There are a number of advantages to using a journaling file system. Both the size and volume of data stored on disk drives has grown exponentially over the years. The problem with a non-journaled file system is that following a crash the fsck (filesystem consistency check) utility has to be run. The fsck utility will scan the entire filesystem validating all entries and making sure that blocks are allocated and referenced correctly. If it finds a corrupt entry it will attempt to fix the problem. The issues here are two-fold. First, the fsck utility will not always be able to repair damage and you will end up with data in the lost+found directory. This is data that was being used by an application but...