Journaling is not need! Clearing up myths about recovery and fast boot

A journaling file system keeps track of changes not yet committed to the file system's using circular log. Its used only to recover after a crash as fast as possible. Its not about safe data or backup data agains corruption.. common misconception of Linux users.

So any ext4/etx3/reiserfs/xfs/btrfs will not guarantee your data integrity "just cos has journal".. is just a way to boot again in conssistency.. and some files will be missing as usually witout journaling..

So you cannot understand then why? well dont worry .. i'll explain you easy with an example...
In the event of a system crash or power failure, such file systems can be brought back online more quickly with a lower likelihood of becoming corrupted.. this is just let's say this is so that it doesn't list invalid files in the filesystem index entries.

When a filesystem breaks, some of its files are not readable, and the filesystem does not understand this (make it slow then), it simply lists a scribble and that's it, journaling helps to not listed and its entry is deleted by example, this is a rough example, but it suffices to say that journaling takes care of the filesystem being usable, since by not understanding the corrupt file it will take a long time to respond.

This is misunderstand as "fast boot after crash" but is not "fast" its just "allow to boot making is fast after recover" and in fact is not a recover per se..

Conclusions:

1. First things first: journalling on ext4 is not mandatory it's optional.
2. Secondly: journalling is not about making the filesystem more resilient, it's about making recovery just valid for.
3. Thirdly: journalling increases the amount of data which is being written to the disk obvisuly so is not "faster" per se!What are the cases that could lead to data corruption?

The absence of journalling itself will never lead to data corruption per se and if you have good batteries on your laptop or your computer has a UPS backup box then is safe to disable it! Of course.. anything else will fails.. so normally people dont do that!