E4DEFRAG(8)

✨ E4DEFRAG(8) · System Manager's Manual ✨

💖 NAME

e4defrag — online defragmenter for ext4 file system 🧚

🎀 SYNOPSIS

e4defrag [ -c ] [ -v ] target ...

🌸 DESCRIPTION

okay so e4defrag is the tool that reduces fragmentation of extent based files 🫶 The file you point it at has to live on an ext4 file system that was made with the -O extent option (see mke2fs(8)) 💅 Once it's done, your file gets more contiguous blocks and it's literally faster to access ✨

target can be a regular file, a directory, or a device that's mounted as an ext4 file system 🦋 If you give it a directory, e4defrag goes through and defrags every file in there. If you give it a device, it finds the mount point and defrags all the files under that mount point. main character energy, fr 👑

🌈 OPTIONS

• -c — this one is a vibe check 🔍 It grabs the current fragmentation count and the ideal fragmentation count, then works out a fragmentation score from them. Looking at that score tells you whether e4defrag should actually be run on the target 💜 If you pair it with -v, you get both counts printed for each file.

It also prints the average data size in one extent 🍓 If you see that number, you can tell whether the file has ideal extents or not. Heads up: the maximum extent size in an ext4 file system is 131072KB (if the block size is 4KB) 🤓

If you use this option, target is never defragmented 🙈 It's just a look, no touching.

• -v — prints error messages, plus the fragmentation count before and after defrag for each file 📣

🦋 NOTES

okay pay attention bestie 💀 e4defrag does not support swap files, files in the lost+found directory, or files allocated in indirect blocks 🙅‍♀️ When your target is a device or a mount point, it won't defrag files that live in the mount point of some other device 🚫

It's safe to run e4defrag on a file while another application is actively using it ✨ The file block contents get copied through the page cache, though, so both e4defrag and the app can slow down because they're fighting over memory and disk bandwidth 😭

If the file system's free space is fragmented, or there isn't enough free space at all, e4defrag might not be able to improve the file's fragmentation 💔

Non-privileged users can run e4defrag on their own files, but if you use the -c option the score doesn't get printed 🥺 So it's really best to run it as the root user 👑

🫶 AUTHOR

Written by Akira Fujita <a-fujita@rs.jp.nec.com> and Takashi Sato <t-sato@yk.jp.nec.com> 💜

🔗 SEE ALSO

mke2fs(8), mount(8) 🌷

that's a wrap, bestie 🎀 e4defrag version 2.0 · May 2009 · E4DEFRAG(8) 💅✨