[lttng-dev] Have live session and rotation together

[Sergei Dyshel]

Thanks! I really missed this feature somehow.

However I see that passing 0 as "tracefile size" will remove size
limitation. Is it possible to disable CTF trace writing altogether?
-- 
Regards,
Sergei Dyshel

On Wed, Apr 22, 2020 at 2:15 AM Mathieu Desnoyers
<mathieu.desnoyers at efficios.com> wrote:
>
> ----- On Apr 21, 2020, at 5:37 PM, Sergei Dyshel qyron.private at gmail.com wrote:
>
> [...]
> >
> >> Considering that there are few compelling use-cases for using both
> >> features together, and no customer have expressed interest in this,
> >> it is not part of our roadmap.
> >
> > Here is my case: I'm using LTTNG for continuous tracing during the
> > whole system timeline,
> > generating pretty big volume of traces.
> >
> > I'm using live and session and Babeltrace2 plugin which converts
> > processes these traces,
> > converts them to text and stores them
> > in some text file to which I apply "logrotate" so that old traces are
> > archived when needed.
> >
> > However, as I see, "lttng-relayd" also writes binary traces in CTF
> > from to some directory, never discarding old traces. So assuming
> > system long runtime this directory is going to eat all the free space
> > sometime?! Rotation would allow me to discard old archives just as
> > "logrotate" does. How else can I discard old CTF files?
>
> The feature you need is called "tracefile rotation", with the channel
> attributes "tracefile count" and "tracefile size". It was implemented at
> the same time as the live mode for exactly the purpose you describe.
>
> See https://lttng.org/docs/#doc-tracefile-rotation for more information.
>
> Thanks,
>
> Mathieu
>
> --
> Mathieu Desnoyers
> EfficiOS Inc.
> http://www.efficios.com