From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Dyshel via lttng-dev Subject: Re: Have live session and rotation together Date: Wed, 22 Apr 2020 00:37:05 +0300 Message-ID: References: <211031090.61650.1587478983634.JavaMail.zimbra@efficios.com> Reply-To: Sergei Dyshel Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-oi1-x234.google.com (mail-oi1-x234.google.com [IPv6:2607:f8b0:4864:20::234]) by lists.lttng.org (Postfix) with ESMTPS id 496H3222lyz1hnF for ; Tue, 21 Apr 2020 17:37:18 -0400 (EDT) Received: by mail-oi1-x234.google.com with SMTP id s202so94966oih.3 for ; Tue, 21 Apr 2020 14:37:18 -0700 (PDT) In-Reply-To: <211031090.61650.1587478983634.JavaMail.zimbra@efficios.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: lttng-dev-bounces@lists.lttng.org Sender: "lttng-dev" To: Mathieu Desnoyers Cc: lttng-dev List-Id: lttng-dev@lists.lttng.org > I do not think this statement is factually correct. I recall that session > rotation was available for sessions being streamed over the network. What > makes you think otherwise ? I think I tried to enable rotation for network streaming session and failed but I don't have 2.11 version currently to reproduce this. > 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? -- Regards, Sergei Dyshel On Tue, Apr 21, 2020 at 5:23 PM Mathieu Desnoyers wrote: > > ----- On Apr 20, 2020, at 4:17 PM, lttng-dev lttng-dev@lists.lttng.org wrote: > > > Hi all, > > > > When creating live session (lttng create --live) I can not enable rotation: > > > > # lttng enable-rotation --size=10M > > Error: Failed to enable size-based rotation schedule on session BX > > This is indeed the expected behavior. > > > > > In LTTNG 2.12 rotation is supported for network streaming mode but it > > was not yet supported in 2.11. > > I do not think this statement is factually correct. I recall that session > rotation was available for sessions being streamed over the network. What > makes you think otherwise ? > > > > > Is there architectural reasons why we can't have live session with rotation? > > Or is it just not implemented yet? In that case in what version is it > > expected to appear? > > It is not impossible design-wise, but would make the implementation much more > complex and require a very significant testing effort. > > 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. > > Thanks, > > Mathieu > > -- > Mathieu Desnoyers > EfficiOS Inc. > http://www.efficios.com