Re: [gentoo-user] emerge --update behavior

[Mark Knecht]

On Mon, Jan 2, 2012 at 9:39 AM, Michael Orlitzky <michael@××××××××.com> wrote:
> On 01/02/12 12:06, Michael Mol wrote:
>>
>> That's the purpose of the "emerge -p" step. Presumably, you would see
>> that there's a package in the list that you're not comfortable with
>> removing, you'd decide you didn't want it removed, and you'd add it
>> back to your world set.
>
> Yeah, I'm not sure I can remove any of them. The only way I see to
> determine what's necessary at this point is to remove it and see if
> stuff breaks.
>

Again, 'equery depends' will tell you if any package locatable through
the @world hierarchy needs the package. No need to uninstall anything
to do that level of investigation. revdep-rebuild -I is also useful,
although more historically than now.

>
>> If you're not comfortable removing *any* package that's in your world
>> set, then, no, there's no way to tell the difference. From this point
>> forward, your best bet is to modify EMERGE_DEFAULT_OPTS to reflect the
>> safest practice for your environment. And start keeping a list of
>> packages installed to meet customers' requests. Portage apparently
>> supports your desired workflow, but it needs to be set up for it.
>>
>> As to recovering from your current scenario...there might be some way
>> to watch your apache processes to identify which files get used over a
>> three-month span, from that list derive a list of which packages were
>> used, and from *that* list, derive a list of which packages weren't
>> used. (Or make an ebuild explicitly identifying the utilized
>> dependencies, and let depclean handle the rest)
>
> That's probably more work than copying everything to another box,
> emptying the world file, and adding things back until stuff works.
>
> Either way the current situation is "you're kinda screwed" which is why
> I proposed avoiding it in the future (for others, too) by fixing --update.
>

Really, the proposal to 'fix --update' doesn't address really knowing
what your system is running and why. Get to the root of that and the
--update thing becomes the non-issue that many of us think it is.

- Mark