improving disk performance by setting noatime

Every time a file is accessed, its inode is updated; this is called the file’s atime. There are similar times recorded when the file is modified (mtime), and created (ctime). But since atime is written every time a file is read, depending on the behaviour of the system this may have a measurable impact on performance.

Nevertheless, note that some application do make use of atime, but they are in the minority.

You can configure the behaviour of the inode update in /etc/fstab via the following settings, see man mount for more detail:

  • atime: update on access
  • noatime: do not update
  • relatime: update atime if it is older than mtime

Through Linux 2.6.29, atime was the default. As of 2.6.30 (9 June 2009), relatime is the default.

You can reset this mount option without restarting the system:

# sudo vim /etc/fstab
dev/sda1 / ext3    defaults,noatime        1 1
# sudo mount -o remount /

To check: $ mount