From owner-freebsd-fs@FreeBSD.ORG Mon Jun 1 08:33:09 2015 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 5284D187 for ; Mon, 1 Jun 2015 08:33:09 +0000 (UTC) (envelope-from andrnils@gmail.com) Received: from mail-wi0-x22a.google.com (mail-wi0-x22a.google.com [IPv6:2a00:1450:400c:c05::22a]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id CEC721CE7 for ; Mon, 1 Jun 2015 08:33:08 +0000 (UTC) (envelope-from andrnils@gmail.com) Received: by wibut5 with SMTP id ut5so31180293wib.1 for ; Mon, 01 Jun 2015 01:33:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=jCP7kQJlkWNZXAq25hJhbugakijqlrlDEllyCcMnOzc=; b=Dgnc0LOJ5fnNFB8tFhGW5GTdjP+4wF8EmIrADQ4JSfDmwVIDiIbbfjxQj8wxwXYU+3 euvct/dayRdrbVPWZ4AGPGnBGIi1yyOE/zHDq/MsnwhtDu1KrQWiJ2k1Fz1zkliaB292 rxpRN+4MgiZnQLII8+fxfFQIVB1KUbB7ZdnhnfJX6acflnfOplePSt3RS/JQs775b/hn sMlmh0zRlw8oGlPE5p9P77SAXoeAcWEGCt2BUWqgWuJWYxbKHVNGxTR5VrzYsyHuiGuW m0iqYpuRb5/1jZaQS6x+HbWwQbrxQU9URJJnnte5qvyQwaKfmKsEjsVAl1cHpcO3L+tp HzJQ== MIME-Version: 1.0 X-Received: by 10.180.91.107 with SMTP id cd11mr17931936wib.51.1433147587138; Mon, 01 Jun 2015 01:33:07 -0700 (PDT) Received: by 10.28.153.10 with HTTP; Mon, 1 Jun 2015 01:33:07 -0700 (PDT) In-Reply-To: <1433146506.14998.177.camel@data-b104.adm.slu.se> References: <1433146506.14998.177.camel@data-b104.adm.slu.se> Date: Mon, 1 Jun 2015 10:33:07 +0200 Message-ID: Subject: Re: [Fwd: Strange networking behaviour in storage server] From: Andreas Nilsson To: =?UTF-8?Q?Karli_Sj=C3=B6berg?= Cc: "freebsd-fs@freebsd.org" Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.20 X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 01 Jun 2015 08:33:09 -0000 On Mon, Jun 1, 2015 at 10:14 AM, Karli Sj=C3=B6berg = wrote: > -------- Vidarebefordrat meddelande -------- > > Fr=C3=A5n: Karli Sj=C3=B6berg > > Till: freebsd-fs@freebsd.org > > =C3=84mne: Strange networking behaviour in storage server > > Datum: Mon, 1 Jun 2015 07:49:56 +0000 > > > > Hey! > > > > So we have this ZFS storage server upgraded from 9.3-RELEASE to > > 10.1-STABLE to overcome not being able to 1) use SSD drives as > > L2ARC[1] > > and 2) not being able to hotswap SATA drives[2]. > > > > After the upgrade we=C2=B4ve noticed a very odd networking behaviour, i= t > > sends/receives full speed for a while, then there is a couple of > > minutes > > of complete silence where even terminal commands like an "ls" just > > waits > > until they are executed and then it starts sending full speed again. I > > =C2=B4ve linked to a screenshot showing this send and pause behaviour. = The > > blue line is the total, green is SMB and turquoise is NFS over jumbo > > frames. It behaves this way regardless of the protocol. > > > > http://oi62.tinypic.com/33xvjb6.jpg > > > > The problem is that these pauses can sometimes be so long that > > connections drop. Like someone is copying files over SMB or iSCSI and > > suddenly they get an error message saying that the transfer failed and > > they have to start over with the file(s). That=C2=B4s horrible! > > > > So far NFS has proven to be the most resillient, it=C2=B4s stupid simpl= e > > nature just waits and resumes transfer when pause is over. Kudus for > > that. > > > > The server is driven by a Supermicro X9SRL-F, a Xeon 1620v2 and 64GB > > ECC > > RAM. The hardware has been ruled out, we happened to have a identical > > MB > > and CPU lying around and that didn=C2=B4t improve things. We have also > > installed a Intel PRO 100/1000 Quad-port ethernet adapter to test if > > that would change things, but it hasn=C2=B4t, it still behaves this way= . > > > > The two built-in NIC's are Intel 82574L and the Quad-port NIC's are > > Intel 82571EB, so both em(4) driven. I happen to know that the em > > driver > > has updated between 9.3 and 10.1. Perhaps that is to blame, but I have > > no idea. > > > > Is there anyone that can make sense of this? > > > > [1]: > > https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D197164 > > > > [2]: > > https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D191348 > > > > /K > > > > > > Another observation I=C2=B4ve made is that during these pauses, the entir= e > system is put on hold, even ZFS scrub stops and then resumes after a > while. Looking in top, the system is completly idle. > > Normally during scrub, the kernel eats 20-30% CPU, but during a pause, > even the [kernel] goes down to 0.00%. Makes me think the networking has > nothing to do with it. > > What=C2=B4s then to blame? ZFS? > > /K > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" > Hello, does this happen when clients are only reading from server? Otherwise I would suspect that it could be caused by ZFS writing out a large chunck of data sitting in its caches, and until that is complete I/O is stalled. Have you tried what is suggested in https://wiki.freebsd.org/ZFSTuningGuide ? In particular setting vfs.zfs.write_limit_override to something appropriate for your site. The timeout seems to be defaulting to 5 now. Best regards Andreas