[pdenton]

IIRC, noatime is useful everywhere except /var/spool or /var/mail where certain daemons may depend on access time correctness.

[londons_explore]

You can't depend on access time correctness... Because someone else can come along and grep through all your files and now they're all accessed right now.

[viraptor]

That's the theory. In practice for example courier IMAP relied (still relies?) on at least relatime for some notification aspects.

[amelius]

Perhaps it just triggers some wasted CPU time, as opposed to incorrect behavior.