ext2 vs. ext3

[mikeshn]

I use Red Hat 7.1 that allows to me use just ext2 file system. I would like to know why ext3 file system is better than ext2.

Thanks in advance

 

[Barnaby W. Füi]

ext3 adds a journal to it. same basic filesystem structure and all that, in fact you can mount it in a machine w/0 ext3 support, and just mount it as an ext2 drive.

basically if the power gets cut or you have to cut the power for whatever reason, it is much better at not corrupting your FS or just generally screwing it up. nothinman can probably explain it better than i can

 

[ProviaFan]

I'm no expert on the technical stuff behind it, but I do know that EXT3FS, as well as ReiserFS and XFS, do not need to be "fsck"ed after a reboot, while EXT2FS and others do. On servers with large (TB-sized) disk subsystems, this could be quite important, as it would knock half an hour or so off bootup time if maintenance were needed.

 

[mikeshn]

fsck?

 

[ProviaFan]

<< fsck? >>


FileSystem Check - sorta like scandisk except for Linux.

 

[Agamar]

True, but I still like forcing a check just to make sure we don't have any corruption.

 

[Bremen]

Basically ext3 is a journaling hack on ext2. AFAIK performance is not that much greater (in fact most likely slower since you have more overhead). A common misconception is that journaling saves your data in the event of a crash. This isn't true, the journaling merely allows the system to figure out whats corrupted without doing a slow check of the filesystem (ie you still lose data).

Anyway, here's a good article to explain journaling and compare the various filesystems, here.

 

[Nothinman]

True, but I still like forcing a check just to make sure we don't have any corruption.

Then why use ext3? You gain nothing else. And you might as well write a script to run cmp or diff on all your files, because fsck only checks the filesystem structures not your data, for integrity.