Linux records information about when files were created and last modified as well as when it was last accessed. There is a cost associated with recording the last access time. The ext2 file system of Linux has an attribute that allows the super-user to mark individual files such that their last access time is not recorded. This may lead to significant performance improvements on often accessed frequently changing files.

chattr +A filename           # File
chattr -R +A  /var/spool/	 # Dir

Or in fstab put noatime