HowTo Disable The "relatime" Method For File "atime" Updates

Overview

atime

The "Access time" field for a file within a given file system is know as: "atime". When a process reads a file, the "atime" field is updated. Disabling "atime" updates, with the "noatime" mount flag, is probably one of the biggest performance tweak that a Linux administrator can make. An active Linux server is continually reading files which generates lots of atime updates. This translates to metadata updates to the file system and writes to disk which can lead to poor I/O performance.

relatime

Relative atime ('relatime') only updates the atime if the previous atime is older than the mtime or ctime. It avoids a lot of metadata atime updates (but not all of them, obviously, there's 'noatime' for that). It's like noatime, but useful for applications like mutt that need to know when a file has been read since it was last modified.