Remount noatime by default

Registered by Paul Sladen on 2007-11-03

Unix includes a feature that stores the 'atime' (access time) for each file in a filesystem. Each access (even if only a read) still causes a write to disk of the updated access time.

A flag called 'noatime' exists to disable writing of access times; enabling 'noatime' by default (at least on Desktops/Laptops) will reduce extra writes to the disk, improving cacheing and positively contributing to power-saving results.

Blueprint information

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Whiteboard

cjwatson: relatime is better. We have already been making progress towards using it by default; a spec is unnecessary.

wolfchri: could be one of the pieces to solve the bug #59695 puzzle. I.e. HD Drives could be re-mounted noatime,nodiratime whenever laptop-mode is enabled. That would significantly reduce write access.

jmccabedansted: I don't think the current version of relatime is good for cases when you want to know roughly how recently the file was accessed (popcon?). Perhaps a patch could be added to fs/inode.c like:
- &inode->i_atime) < 0)
+ &inode->i_atime) < 0 &&
+ now.tv_sec-(24*3600) < &inode->i_atime.tv_sec )

(?)

Work Items

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