Re: [evlog-dev] Implementation questions

Hello Benoit,

See my reply below=20

On Mon, 2004-04-19 at 07:00, Benoit Guillon wrote:
> Hello,=20
>=20
> I'm sorry to bother you again, but I have some questions about the
> evlog implementation (1.0.6-b2) and its scope:=20
>=20

No problem, I am glad that you are still with us :-)
> * Is it necessary to fork evlogd to manage kernel events? Why not
> using a thread, since it would make synchronization cleaner (a mutex
> is then enough)? Besides, on some implementations thread use is
> lighter than process fork.=20

We have to use either a separate process (via fork) or a separate
thread, because the code that drains the kernel buffer can't use
select() or poll().  We avoided implementing stuff using threads because
it wasn't clear that POSIX threads would find their way into standard
Linux. Also, I'm not sure whether do_syslog() is (or needs to be)
thread-aware.

> * For TCP backend, BACKENDS_DIR is set to "EVLOG_PLUGINGS_DIR" string.
> I think it should be set to the macro EVLOG_PLUGINS_DIR instead.=20

Yes, the BACKNENDS_DIR should be set to EVLOG_PLUGIN_DIR. Thanks for
poiting this out, I will upload an update for evlog soon.

> * As far as I can understand, all the backends are called for each
> event. That is the available backends or their configuration
> (Disable=3Dyes in the config file) that selects the backends used. Is i=
t
> possible to filter the backend(s) to use according to the event? For
> instance, it could be interesting to be able to "route" some kinds of
> events (e.g. facility=3DLOCAL4) to a centralized evlogd, and to let
> other events locally on the machines.

The current design sends all events that go to the log file to
backends. One could write a backend to filter out some events and only
route some specified events. If you are interesting in writing one, I
could give some helps.

>  It is not possible if the TCP backend is used for all the events.

I am not sure I understand this question, but TCP backend is used to
forward all events that go to the log file to a remote host.

> * Is it possible to use IBM Director combined to evlog ELA feature, or
> is IBM Director techno incompatible?=20

We are currently working with IBM Director experts on the integration of
evlog Error Log Analysis with IBM Director.
>=20
> Thansks for your answers,=20
>=20
> Bye,=20
> --
> Beno=C3=AEt Guillon                [email protected]=20
> =20



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