atime values

atime is a standard file attribute that represents the time when the file was last accessed.

The -S file system configuration parameter controls how the atime value is updated. The default is -S no, which results in updating atime locally in memory whenever a file is read, but the value is not visible to other nodes until after the file is closed. If an accurate atime value is needed, the application must use the GPFS™ calls gpfs_stat() and gpfs_fstat() functions. When -S yes is specified, or the file system is mounted read-only, the updating of the atime value is suppressed. This means that the atime value is no longer updated. This can be an issue if you have policies that use the ACCESS_TIME file attribute for file management. For more information, see Exceptions to Open Group technical standards.

When -S relatime is specified, the file access time is updated only if the existing access time is older than the value of the atimeDeferredSeconds configuration attribute or the existing file modification time is greater than the existing access time.