From owner-freebsd-questions@FreeBSD.ORG Tue Nov 22 21:58:19 2011 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5370F1065672 for ; Tue, 22 Nov 2011 21:58:19 +0000 (UTC) (envelope-from kjkoster@gmail.com) Received: from mail-gy0-f182.google.com (mail-gy0-f182.google.com [209.85.160.182]) by mx1.freebsd.org (Postfix) with ESMTP id 0F7158FC0A for ; Tue, 22 Nov 2011 21:58:18 +0000 (UTC) Received: by ghbg15 with SMTP id g15so402147ghb.13 for ; Tue, 22 Nov 2011 13:58:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=subject:mime-version:content-type:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to:x-mailer; bh=+ZGVLZ4RxG4rfs6NJg6Xbvn2+UcH2eijOqZWoBp429M=; b=G49lJCVtHhR9kuMwGwc3ijumsSTEME6pKS8lVTD431sJIHwOrtXPU2TygZesan462U UUqkPDMJt24JuvqciPR8jgxgKSSkwOAsfaqOCxWg4fijnBhYtiNbm5F6DRsimM4PLKHY QRN+/7UaMqSaE282rwU7pPWL87hm+7wKut2UU= Received: by 10.213.21.131 with SMTP id j3mr1132674ebb.95.1321999097797; Tue, 22 Nov 2011 13:58:17 -0800 (PST) Received: from macbookpro.fritz.box (kjkoster.org. [83.163.197.206]) by mx.google.com with ESMTPS id 5sm45762796eev.2.2011.11.22.13.58.16 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 22 Nov 2011 13:58:16 -0800 (PST) Mime-Version: 1.0 (Apple Message framework v1251.1) Content-Type: text/plain; charset=iso-8859-1 From: Kees Jan Koster In-Reply-To: <2973_1321996526_4ECC10EE_2973_123_1_D9B37353831173459FDAA836D3B43499D2C69D77@WADPMBXV0.waddell.com> Date: Tue, 22 Nov 2011 22:58:14 +0100 Content-Transfer-Encoding: quoted-printable Message-Id: <4B28ADC5-8325-442E-8F02-9AE3535D8C6D@gmail.com> References: <2973_1321996526_4ECC10EE_2973_123_1_D9B37353831173459FDAA836D3B43499D2C69D77@WADPMBXV0.waddell.com> To: Gary Gatten X-Mailer: Apple Mail (2.1251.1) Cc: "'freebsd-questions@freebsd.org'" Subject: Re: Diagnosing packet loss X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 Nov 2011 21:58:19 -0000 Dear Gary, Thank you for your reply. Your comment about dupe IP triggered something = that I failed to mention: the interface is aliased. It has two IP = addresses. IP address a and it has an alias IP address b. I just tested = binding mtr to each of these interfaces separately to measure packet = loss. If I use mtr to measure packet loss from saffron (the stricken machine) = to cumin (another machine in a different data center) I see the = following: saffron (ip address a) -> cumin: packet loss saffron (ip address b) -> cumin: no packet loss cumin -> saffron (ip address a): packet loss cumin -> saffron (ip address b): no packet loss This is consistent from running mtr for 5 minutes straight. This to me = shows that the hardware is fine. Using the alias IP address I can run = with no packet loss for as long as I like. Hum.... Could it be that my switch does not support IP aliasing? Then = why is there packet loss only on one IP and not on both? This is getting weirder and weirder. Kees Jan On 22 Nov 2011, at 22:15, Gary Gatten wrote: > Well, 1% is not good but I've seen worse for sure! Sounds like you = tried the obvious. I would recommend a different IP to rule out a dupe = ip; else it must be NIC related - either hardware or driver. Also, = perhaps swap cables and ports with a working machine and see if the = problem follows or stays put. >=20 > ----- Original Message ----- > From: Kees Jan Koster [mailto:kjkoster@gmail.com] > Sent: Tuesday, November 22, 2011 02:33 PM > To: freebsd-questions@freebsd.org > Subject: Diagnosing packet loss >=20 > Dear All, >=20 > I am stuck with a machine that shows serious packet loss (about 1% of = all traffic is dropped). I tried the obvious (new network cable, = different switch port, different ethernet interface on the machine), but = the problems remain. >=20 > Another machine that sits in the same rack and is hooked up to the = same switch shows no such packet loss issues. The problematic machine is = a dual Opteron with FreeBSD 8.2-STABLE from Thu Aug 11 14:05:47 CEST = 2011. >=20 > The machine is lightly loaded. A MySQL slave is running, but the = machine is not serving queries. Plus a Munin server process. >=20 > I am at a loss where to start diagnosing this. Can you advise me where = to look? Are there network buffers that may be overflowing? > -- > Kees Jan >=20 > http://java-monitor.com/ > kjkoster@kjkoster.org > +31651838192 >=20 > Change is good. Granted, it is good in retrospect, but change is good. >=20 > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to = "freebsd-questions-unsubscribe@freebsd.org" >=20 >=20 >=20 >=20 >=20 > >
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> "This email is intended to be reviewed by only the intended recipient > and may contain information that is privileged and/or confidential. > If you are not the intended recipient, you are hereby notified that > any review, use, dissemination, disclosure or copying of this email > and its attachments, if any, is strictly prohibited. If you have > received this email in error, please immediately notify the sender by > return email and delete this email from your system." > >=20 -- Kees Jan http://java-monitor.com/ kjkoster@kjkoster.org +31651838192 I hate unit tests; I much prefer the illusion that there are no errors = in my code. -- = Hendrik Muller