This directory contains an array of options and information concerning various aspects of the file system, including quota, file handle, inode, and dentry information.
The binfmt_misc/ directory is used to provide kernel support for miscellaneous binary formats.
The important files in /proc/sys/fs/ include:
  • dentry-state — Provides the status of the directory cache. The file looks similar to the following:
    57411	52939	45	0	0	0
    The first number reveals the total number of directory cache entries, while the second number displays the number of unused entries. The third number tells the number of seconds between when a directory has been freed and when it can be reclaimed, and the fourth measures the pages currently requested by the system. The last two numbers are not used and display only zeros.
  • dquot-nr — Lists the maximum number of cached disk quota entries.
  • file-max — Lists the maximum number of file handles that the kernel allocates. Raising the value in this file can resolve errors caused by a lack of available file handles.
  • file-nr — Lists the number of allocated file handles, used file handles, and the maximum number of file handles.
  • overflowgid and overflowuid — Defines the fixed group ID and user ID, respectively, for use with file systems that only support 16-bit group and user IDs.
  • super-max — Controls the maximum number of superblocks available.
  • super-nr — Displays the current number of superblocks in use.