From Newsgroup: alt.os.linux.ubuntu
On Wed, 15 Apr 2026 06:57:27 +1000, Axel wrote:
https://www.tomshardware.com/service-providers/web-hosting/friends-gif-cripples-website-discussion-platform-backup-with-377-gigabytes-of-rachels-happy-dance-1-6mb-animation-was-replicated-246-173-times-breaking-filesystem-limit
Out of curiosity, I had a look into what exactly were the capabilities
of ext4. Turns out this 64K limit is just a default setting.
Exhibit A: <
https://manpages.debian.org/link(2)>, description of the EMLINK error:
EMLINK
The file referred to by oldpath already has the maximum number
of links to it. For example, on an ext4(5) filesystem that
does not employ the dir_index feature, the limit on the number
of hard links to a file is 65,000; on btrfs(5), the limit is
65,535 links.
Exhibit B: <
https://manpages.debian.org/ext4(5)>, relevant filesystem initialization options:
dir_index
Use hashed b-trees to speed up name lookups in large
directories. This feature is supported by ext3 and ext4 file
systems, and is ignored by ext2 file systems.
Doesn’t actually mention any link limit, but the next one does:
dir_nlink
Normally, ext4 allows an inode to have no more than 65,000
hard links. This applies to regular files as well as
directories, which means that there can be no more than 64,998
subdirectories in a directory (because each of the '.' and
'..' entries, as well as the directory entry for the directory
in its parent directory counts as a hard link). This feature
lifts this limit by causing ext4 to use a link count of 1 to
indicate that the number of hard links to a directory is not
known when the link count might exceed the maximum count
limit.
--- Synchronet 3.21f-Linux NewsLink 1.2