Re: [ECFT] pkgng 0.1-alpha1: a replacement for pkg_install

On Fri, Mar 25, 2011 at 2:38 PM, Alexander Leidinger
<Alexander_at_leidinger.net> wrote:
> Quoting Baptiste Daroussin <bapt_at_freebsd.org> (from Fri, 25 Mar 2011
> 15:14:52 +0100):
>
>> 2011/3/25 Alexander Leidinger <Alexander_at_leidinger.net>:
>>>
>>> Quoting Baptiste Daroussin <bapt_at_FreeBSD.org> (from Fri, 25 Mar 2011
>>> 11:11:11 +0100):
>>>
>>>> pkgng is a binary package manager written from scratch for FreeBSD.
>>>
>>> I didn't had a look at it, just some comments about some parts you
>>> explained.
>>>
>>>> features supported are or will be :
>
>>>> - a special architecture "all" allows to specify when a package can be
>>>> used
>>>> on every architecture. (not done yet)
>>>
>>> What if a package is able to install on a subset, e.g. the linuxulator
>>> ports
>>> are for amd64 and i386?
>>>
>>
>> No clue for that at the moment but we are open to suggestions.
>
> The suggestion is easy, allow a way to specify a set of valid architectures.

That looks reasonable and easy to implement.

>
>>> What about DB corruption/loss? Do you keep the /var/db/pkg/<package>/xxx
>>> files even with pkgng and only use the DB as a way to speed up some work
>>> (so
>>> the DB corruption just requires to run pkg2ng), or are you lost of the DB
>>> is
>>> lost?
>>>
>>
>> Nothing is done about DB corruption/loss, I am not sure we need to do
>> something.
>> Maybe.
>
> I would say "for sure". Info: In Solaris 10 sqlite is used for the service
> managenemt framework (SMF). It is possible that the DB is corrupt in some
> bad situations. In this case you have to rebuild the DB (script provided,
> been there, had to use it).

If sqlite is properly used with transactions, it is very hard to
corrupt the database. But if hardware lies to us and say that the data
is on disk whereas it isnt... what can we do?
Another potential problem is fsync(), but if it is broken on FreeBSD
we want to fix it!

BTW, the goal is to only have the database and not the flat files.
If you are paranoid about power outage, use something like zfs snapshots...

>
>> Currently a filesystem corruption/loss on /var/db/pkg would do the same.
>
> Put a corruption of /var/db/pkg/xyz-1/+REQUIRED_BY would only affect a small
> part, and this part could be even recovered from (pkgdb from portupgrade is
> able to do it).

With sqlite we have atomicity! And locks!

>
>> but it is sqlite so we can perhaps provide a way to get compressed
>> dump so user can periodically backup their database.
>
> It needs to be automated. Maybe periodic daily... but maybe this is not
> often enough after a day of a lot of changes (think about it this way: do
> you want to lose a day of changes?). The current FS based DB is very robust,
> partly because there is redundant data, pertly because losing a file just
> means that the very limited subset of information is lost (and a reinstall
> of one port will fix it).
>
> Bye,
> Alexander.

Regards,
Julien