From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mathieu Desnoyers via lttng-dev Subject: Re: Have live session and rotation together Date: Wed, 22 Apr 2020 15:00:39 -0400 (EDT) Message-ID: <2090780417.64200.1587582039964.JavaMail.zimbra@efficios.com> References: <211031090.61650.1587478983634.JavaMail.zimbra@efficios.com> <1540290911.63019.1587510939096.JavaMail.zimbra@efficios.com> Reply-To: Mathieu Desnoyers Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail.efficios.com (mail.efficios.com [167.114.26.124]) by lists.lttng.org (Postfix) with ESMTPS id 496qWy52Kmz1j5Q for ; Wed, 22 Apr 2020 15:00:46 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id 5F7EB24F559 for ; Wed, 22 Apr 2020 15:00:40 -0400 (EDT) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: lttng-dev-bounces@lists.lttng.org Sender: "lttng-dev" To: Sergei Dyshel Cc: lttng-dev List-Id: lttng-dev@lists.lttng.org ----- On Apr 22, 2020, at 2:18 PM, Sergei Dyshel qyron.private@gmail.com wrote: > 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? No, because the relay daemon uses the on-disk files as intermediate storage between the receiving end and the part interacting with live viewers. Note that https://bugs.lttng.org/issues/1182 tracks a known issue where the relay daemon mishandles tracefile-count == 0 and tracefile-size != 0. It has not been a priority to fix this issue so far. Thanks, Mathieu > -- > Regards, > Sergei Dyshel > > On Wed, Apr 22, 2020 at 2:15 AM Mathieu Desnoyers > wrote: >> >> ----- On Apr 21, 2020, at 5:37 PM, Sergei Dyshel qyron.private@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 -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com