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Re: Re: RFC: Making mail-transport-agent Priority: optional

Adam Borowski wrote:
> On Wed, Oct 12, 2011 at 02:39:13PM -0700, Josh Triplett wrote:
>> Popcon shows that ~65-70% of Debian systems have exim4 installed.
>> 30-35% of users cared enough to remove exim, and another 7% or so seem to
>> have configured their systems to stop running it (at boot or otherwise)
>> without actually removing it.
> That would break their system as daemons have no way to notify the user
> something is wrong.

Not true.  Daemons can write to log files, as almost all daemons other than
cron do.

> Instead, I bet that you read popcon's vote<installed
> that way -- which at least in this case nearly always means the user has the
> filesystem mounted noatime.

Fair enough.  I took a guess, based on exim running at boot, but noatime
would certainly produce the same effect.  I use noatime myself.  (I also
don't run popcon myself.)

The 30-35% figure for users who have removed exim still make sense,
though, to the extent that popcon numbers for a package with priority >=
standard can make sense.

In any case, I didn't intend the popcon numbers as any kind of proof,
just a bit of very rough evidence about how many people have removed an
MTA.  For comparison, ~15% of users don't have wamerican (standard, with
numerous alternatives), ~15% of users don't have mutt (standard), ~15%
of users don't have w3m (standard for some reason, with numerous
alternatives), ~14% of users don't have ncurses-term (standard), ~10% of
users don't have telnet (standard), and ~4% of users don't have pciutils
(standard).  I haven't checked the full list of standard packages, but
it does seem notable that of standard packages, exim gets removed much
more frequently than others.

That said, I'd hardly argue for popcon numbers as any significant reason
against having an MTA in standard.  I provided a pile of much better
reasons in my original mail.

> Which is a damn reasonable thing to do, as it prevents every write from
> having its metadata cost doubled.  Current Debian's default, relatime,
> sacrifices performance and causes unnecessary spin-ups, with the stated
> explanation being certain uses of mbox, a long-obsolete format that might be
> adequate at most for rare mail from daemons but not actual mail from live
> people[1].  And even that is fixable by making mail readers manually set the
> access time.

Agreed on all counts.  The one other argument I've seen for relatime
involves tmpreaper and similar programs which prune files by age.  The
original commit that put relatime into the kernel
(11ff6f05f1e836a6a02369a4c4b64757e484adc1) cited tmpreaper as a

- Josh Triplett

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