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From: Douglas Graham <douglas.graham@ericsson.com>
To: "lttng-dev@lists.lttng.org" <lttng-dev@lists.lttng.org>
Subject: Fast way to clear trace logs and continue tracing?
Date: Wed, 14 Dec 2016 02:41:38 +0000	[thread overview]
Message-ID: <DB5PR07MB0949E65A3F1EEFBEDD89CD79F09A0__49093.2830529802$1481683320$gmane$org@DB5PR07MB0949.eurprd07.prod.outlook.com> (raw)

Hi,

I just started working with lttng recently, so apologies if this is a dumb question.

Suppose I have configured and started a session and have collected a bunch of traces in a trace file.  Now I want to clear those traces but then continue saving new traces using the same session.  Is there a reasonably fast way to do that?

What we currently do is "lttng save --output-path=x.cfg; lttng stop; lttng destroy; rm -rf <tracedir>; lttng load --input-path=x.cfg

But this is very slow in some cases.  The lttng load in particular is extremely slow when Linux is running inside a virtual machine.  I was hoping that lttng might support a "lttng clear" that could be used to remove all traces from the trace file, but I can't find any such command.

I note that lttng does support the rotating of trace files when they reach a size limit.  I think that's fairly close to what I want.  If I could force a trace file rotation at an arbitrary time and then simple remove the old rotated log, leaving the new one, that seems like it should do the job.  Except I don't see any way to force a rotation.

Any ideas?

Thanks,
Doug
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             reply	other threads:[~2016-12-14  2:43 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-14  2:41 Douglas Graham [this message]
     [not found] <DB5PR07MB0949E65A3F1EEFBEDD89CD79F09A0@DB5PR07MB0949.eurprd07.prod.outlook.com>
2016-12-14 16:59 ` Fast way to clear trace logs and continue tracing? Jonathan Rajotte Julien
2016-12-14 19:47 Douglas Graham
     [not found] <DB5PR07MB0949C5E0DCAC553185E0D24DF09A0@DB5PR07MB0949.eurprd07.prod.outlook.com>
2016-12-14 23:30 ` Jonathan Rajotte Julien

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