Tunable Kernel Parameters

File System Subsystem
Open or Locked Files Parameters
Chapter 4
29
Open or Locked Files Parameters
Open and Locked Files
Individual processes can open one or more files for reading or writing, and it is not
uncommon for a process to have many files open at the same time; particularly in large
database applications, for example.
Furthermore, mail, database, and other applications often require simultaneous access
to a given file by two or more processes. To prevent file or data corruption, a process that
is altering the contents of a file must be able to lock the file against conflicting uses until
it is safe to release control of the file.
Open and locked files require memory and other system resources. These resources must
be balanced against other system needs to maintain optimum overall system
performance. Use nflocks to limit the combined total number of file locks that are
available system-wide to all processes at any given time.
Limits
Two parameters, maxfiles and maxfiles_lim, respectively, govern the soft and hard
limits on the number of files a process can open simultaneously. nfile governs the
maximum number of files that can be open on the entire system at any given time.
Additional Information
• “Open or Locked Files Parameter Summary” on page 25