The difference in file size between Symbolic and Hard links

filesystemshard linksymlink

I plan to keep all my movies in one giant folder, and then create other folders for the genres, while creating links for all the movies in the genre folder. This way I can organize movies into multiple genres without unnecessarily copying them.

I've been planning to use hard links in this endeavor in order to create a more robust system in which I may be able to move files around without breaking links. However, I'm wondering if hard links will take more storage space than symbolic links and bloat my machine. I've created soft and hard links to files to test this, but they both show the original file size when I look at file size under preferences in Thunar.

Which file takes more hard drive space, Symbolic Links, or Hard Links?

On a semi-unrelated side note, does xbmc / kodi recognize links to videos as actual videos?

Best Answer

Symbolic link files take more space. Hard linked files share the same inode; but a symbolic file is a pointer to the original (location).

Despite that, there are two caveats for hard links:

Not all file system support hard links.
Hard links cannot be applied for folders.

I guess you do not need to consider about the storage issue since in most of the cases they are trivial. In addition, there might be some tools helping you organize genres virtually (they may take advantages of virtual file systems).

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Symbolic link and hard link questions

. is actually the current working directory in either case; it has nothing to do with the directory holding the script:

[/tmp] $ echo "realpath ." > test.sh && chmod +x test.sh
[/tmp] $ /tmp/test.sh
/tmp
[/tmp] $ cd /usr/bin
[/usr/bin] $ /tmp/test.sh
/usr/bin

Do Symbolic Links Affect Disk Usage? – Detailed Analysis

Symbolic links do take room, of course, but just the room it takes to store the name and target plus a few bytes for other metadata. The space taken by a symbolic link does not depend on the space taken by the target (after all, the target is not even required to exist).

Plain du reports the space taken by a directory tree on the disk. du -L reports the space that would be taken by a directory tree if all symbolic links were replaced by their target. The former is usually the useful information; for example, it's the space you'd recover if you deleted the tree, and it's (approximately) the space you need to back up the tree.

du on a directory tree shows (usually) a little more than the total of the file sizes. That's due to two things. First, du also counts directories, which take a little room to store file names and metadata. Second, du counts the disk space taken by a file, which can be different from the file size: the most common effect is that files take up an integer number of blocks (4kB on a typical Linux installation), so a 1-byte file can show as 4kB in du output; but compression (such as the primitive form provided by sparse files on just about every unix filesystem) can make the file size larger than its disk usage.

From the numbers you give, it appears that Thunar reports the sum of the sizes of the files in the directory tree, following symbolic links. It's actually saying so in a subtle way — it's claiming that the total size is 570.3 kB, not that the disk usage is 570.3 kB. What is not at all apparent from the user interface or documentation is that Thunar follows symbolic links when computing the size.

Which one is “right” is a subjective matter. du reports disk usage. Thunar reports total size following symbolic links. Creating a symbolic link has a negligible impact on disk usage, but by definition does change total-size-following-symbolic-links that Thunar reports.

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Do Symbolic Links Affect Disk Usage? – Detailed Analysis

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