On 2024-01-09 00:47, Olivier Certner wrote:
Why not make noatime the default across the whole system? Outside of mbox
why is recording access time actually useful?
Exactly.
I've never found any compelling reason in most uses to enable "atime",
except
perhaps local mail but as addressed in other answers it is a relic of the
past
mostly irrelevant today. And its drawbacks are well known and can be
serious.
The auditing use is not what I consider "normal" in the sense I suspect it
concerns a small minority of users (maybe even tiny). Plus, serious
auditing
requires keeping a log (generally immutable) of accesses, i.e., more than a
single
time and, as pointed out in another answer, at least the ID of the user
performing
the access. Updating the access time field on files/directories doesn't
address
both.
What "relatime" only gives you is a guarantee that you know that some file
has
been accessed at some point after its last modification (or creation), and
that
the access time is correct if precision is only a day. It also generally
lowers
I/O obviously, but not in some scenarios (file creation and subsequent
read).
So, to me, at this point, it still sounds more than a gimmick than something
really useful. If someone has a precise use case for it and motivation,
than of
course please go ahead.
In the short term, I'd vote for turning "atime" off by default.
Thanks and regards.
Honestly! Why do we have to upend decades of usage and understanding? Just
because
it's old doesn't mean it's wrong. Several weeks of replies confirm my initial
belief --
atime as it is currently implemented, is as it should be.
Administrators and users have spent years to decades finessing their systems
and
policies based on the way the OS works. In fact administrators and users
*pick* their
OS based on the way it works. In the case of atime; decades of
scripting/policy and
utilities have been created based upon the it's expected behavior on any
given OS.
I haven't seen anything in this thread that wouldn't be better placed in
tuning(7)
or tunefs(8).
* Silicon disks fail without warning
tapes did as well. Unless you're working with punch cards please implement
an
effective backup strategy -- snapshot(8)
* writing to my disk takes a long time
see tuning(7) or tunefs(8)
* atime doesn't work like "realtime" does on Linux
use Linux instead or add the ability to also use realtime
Security and forensics are good reasons to keep atime unchanged. Any
discussion
regarding changes to it's current behavior seems folly or bikeshedding.
Apologies for the "attitude".
--Chris
