Where is the journal stored?

I was reading trough the link on journaling-filesystems and i would like to know where exactly is the journal stored in my Harddisk.

Some pointers on this image shown below

Thanks,
Sen

There is no fixed place for the journal, each filesystem stores it in a different place.

If you are expecting it to be a regular file, then your are mistaken, it's more like a part of the filesystem structure like the inode table. The funny point is that ext3/4 treats it exactly like a regular file. It is usually found in the inode number 8, but this is a kernel parameter that can be changed at compile time.

If you want to get technical, this article by Carlo Wood, written in March 2008, is a great read about the ext3 structure.

If you don't mind put journal in a place with words like partition table, inode or block and don't worry about it:

The journal is stored in a separate space of the partition, you cannot access it directly. You can use sudo debugfs /dev/sda# where the # symbol is the number of your partition, and then using logdump in debugfs to print it out. The output is confusing though.

Generally, as a regular user, you don't need to know about the journal. Using ext3/4 will be sufficient to prevent data loss (in most cases).

This link might help: http://www.linuxforums.org/forum/red-hat-fedora-linux/121074-ext3-journal.html