Debian – Significant difference in speed between fsck using ext3 and ext4 on Debian Squeeze

debianext3ext4fsck

Recently I installed Debian Squeeze, first using ext3 and then again using ext4 on the same machine. The automatic fsck done after a certain number of mounts is much faster using ext4 (about 1 min) than ext3 (about 5 min).

What are the reasons for this significant difference in speed? If ext4 is much faster why does the Debian installer default to using ext3?

Best Answer

That's one of the most advertised benefits of ext4 (see it mentioned in the Features on Wikipedia).

The reason? Filesystem developers worked hard to achieve this.

Here's a short summary quoted from Wikipedia:

Faster file system checking

In ext4, unallocated block groups and sections of the inode table are marked as such. This enables e2fsck to skip them entirely on a check and greatly reduces the time it takes to check a file system of the size ext4 is built to support.

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