Cannot mkdir: Too many links

Question

I'm trying to untar several tar files. I encountered something like this

tar: NCBI_SRA_Metadata_Full_20110601/SRA037312: Cannot mkdir: Too many links

Is there a limit to the number of files that can exist in a directory? I checked du -i the IFree is still 51M. So it doesn't looks to me like inode is running out.

Solution

Yes, there is a limit to the number of files that can exist in a directory. That limit depends on what file system you're using though, and potentially on what options were used when you formatted the file system.

By default on ext3 (and I believe ext2 as well), the limit is 32,000 files.

EDIT: Further reading, as well as my own testing, suggest that the 32,000 file limit is no longer an issue in modern kernels with ext3. However, there is still a 32,000 sub-directory limit, so while JdeBP's comments are technically correct, that huggie asked, and I answered the wrong question... the gist of the answer is the same.

Consider this test:

$ mkdir asdf
$ for x in $(seq 1 32000); do mkdir $x; done
mkdir: cannot create directory `31999': Too many links
mkdir: cannot create directory `32000': Too many links

Comments

[JdeBP]

You've asked the wrong question. You're making a subdirectory, as the error message tells you. You should therefore be asking about limits on subdirectories within a directory, not on files. (There are limits on files. But the EMLINK error here results from a different limit on subdirectories.)