Bug#522507: exim4-base: debin/control::Depends add anacron

[Andreas Metzler]

On 2009-04-07 Jari Aalto <jari.aalto at cante.net> wrote:
> Andreas Metzler <ametzler at downhill.at.eu.org> writes:

>>>>> The Depends line reads:
>>>>>    ..., cron | fcron,

>>>>> Please add also 'anacron' to the choices.
>>>> [...]

>>>> I think that should be ok. The non-acceptance of the anacron
>>>> alternative probably dates back to exim3 days, when exim was running
>>>> from inetd and the queue-runners were started by a cronjob.

>>> To my knowledge, anacron is not a cron drop-in replacement and needs
>>> cron itself to run. See also, /usr/share/doc/anacron/README.Debian.

>> Good point. I missed that.

>> Afaict without cron installed the jobs would only be run up at startup
>> (by the init script) or on laptops using APM for power management when
>> switching to AC-power.

>> I agree it is a bug (260323, fixed in Ubuntu afaict) that anacron has no
>> ACPI support yet. However I wonder whether the current state of
>> affairs is not "good enough" for exim, the cron job could be run less
>> often without big negative effects imho. For reference, logrotate also
>> accepts the anacron alternative.

> The dependency already includes fcron:

>      ...a scheduler. It implements most of Vixie Cron's functionalities.
>      But contrary to Vixie Cron, fcron does not need your system to be
>      up 7 days a week, 24 hours a day: it also works well with systems
>      which are running neither all the time nor regularly.

> anacron is no different

Anacron differs a lot. Anacron extends cron. Fcron has the featureset
of cron and anacron combined. It can run regular cronjobs but can
*also* catch up jobs that should have been run when the machine was
not running.

On the other hand anacron _without_ cron installed is crippled. It
*only* works reasonably (i.e. daily cron jobs are run daily) if the
machine is regularily (daily) powered off. APM supported labtops that
are plugged in daily  should also work. Modern Laptops using ACPI (and
suspend to disk instead of shutdowns) will not have the cron.daily
(weekly/monthly) jobs run at all. The same applies to a machine
running 24/7 that has anacron (accidentally) installed without cron.
/etc/cron.hourly/ is not supported by anacron at all.

Exim has not got any specific requirements, except that the daily
cronjob should be run at some point. It is probably not crucial to
run it daily at a leafsite (personal workstation), but not running at
all (24/7 machine acting as mailserver without crond) is not a good
thing.

Why the reluctance installing crond anyway?

cu andreas

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