mount - relatime / noatime

장비를 살펴보다 보니 noatime 대신 relatime 이라는게 보여서 검색을 해보니..
SSD 나 SD 메모리에서 noatime과 비슷하게 쓰이지만
noatime은 access time을 전혀 갱신하지 않는데 반해(정확하게는 커널 기본값으로 제어됨)
relatime은 access time이 현재 수정/교체 시간보다 이를때에만 업데이트 하도록 한다.(먼소리야!!)
아무튼.. 조금은 더 스마트~하게 atime을 쓰기에
noatime > relatime > atime 순으로 inode에 접근하는 빈도가 적을듯 하다.

atime Do not use noatime feature, then the inode access time is controlled by kernel defaults. See also the description for strictatime and relatime mount options. noatime Do not update inode access times on this filesystem (e.g, for faster access on the news spool to speed up news servers). relatime Update inode access times relative to modify or change time. Access time is only updated if the previous access time was earlier than the current modify or change time. (Similar to noatime, but doesn't break mutt or other applications that need to know if a file has been read since the last time it was modified.) norelatime Do not use relatime feature. See also the strictatime mount option. strictatime Allows to explicitly requesting full atime updates. This makes it possible for kernel to defaults to relatime or noatime but still allow userspace to override it. For more details about the default system mount options see /proc/mounts. nostrictatime Use the kernel's default behaviour for inode access time updates. [링크 : http://linux.die.net/man/8/mount]

--time=WORD with -l, show time as WORD instead of modification time: atime -u, access -u, use -u, ctime -c, or status -c; use specified time as sort key if --sort=time [링크 : http://linux.die.net/man/1/ls]

[링크 : http://unix.stackexchange.com/questions/8840/last-time-file-opened] 


커널 2.6.30 이후 부터 relatime이 기본값으로 변경되었다고 한다.
[링크 : http://unix.stackexchange.com/questions/17844/when-was-relatime-made-the-default]