From owner-freebsd-geom@FreeBSD.ORG Mon Oct 20 13:39:21 2014 Return-Path: Delivered-To: freebsd-geom@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 0C4D5825 for ; Mon, 20 Oct 2014 13:39:21 +0000 (UTC) Received: from mail-ie0-f173.google.com (mail-ie0-f173.google.com [209.85.223.173]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id CE7D26EF for ; Mon, 20 Oct 2014 13:39:20 +0000 (UTC) Received: by mail-ie0-f173.google.com with SMTP id tp5so4700083ieb.18 for ; Mon, 20 Oct 2014 06:39:14 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:content-type; bh=RrCCT6Xy/8nrsWOgn/xnh91nJ7L3PDegG2jEHk/ohqU=; b=c8aWz0HLfVluTmDrt1eGQFaBJANSHAS/8oBrG95OoflNtN06trgLi2DRdtSRXMNmlC nu/n8HE6aZP6VcYEMRYwnSgtoCpxXjIFO9OgzPaWzn0j/6ScOExaQhE8XCWc/iKpzJSs /nK5Fh438Xx9C1EgaK07rLMlc/8JpULL0gWJGxcLHq0Yp0GCAXD87pb5pB1gQYWY/GX9 n1J0UtnUuZIaeMn/6AafzPAwW+Y3ehyv0mO5P8QQOe8Pf8GvUHu4Ph4VqHpDsW1miABr +ggyu+I5/U3i3j+R55SuVMqk8PYALn1fTL00/oDT5ZsXwQO5eL2gcPYk3YZ0SgcSo5+9 N4bQ== X-Gm-Message-State: ALoCoQkBE5ozFSNl52neYd1VBWhVe+faTjvBEhgGaQ2s3ZBYM2KBeHaIZEVh4weIqBk8FjqakOx9 MIME-Version: 1.0 X-Received: by 10.42.8.70 with SMTP id h6mr2101700ich.85.1413812354335; Mon, 20 Oct 2014 06:39:14 -0700 (PDT) Received: by 10.107.9.8 with HTTP; Mon, 20 Oct 2014 06:39:14 -0700 (PDT) In-Reply-To: <20141017165849.GX1852@funkthat.com> References: <20141017165849.GX1852@funkthat.com> Date: Mon, 20 Oct 2014 19:09:14 +0530 Message-ID: Subject: Re: geom gate network From: Sourish Mazumder To: Sourish Mazumder , freebsd-geom@freebsd.org Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.18-1 X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 20 Oct 2014 13:39:21 -0000 I am willing to test out the patches on my setup. Please send me the patches. On Fri, Oct 17, 2014 at 10:28 PM, John-Mark Gurney wrote: > Sourish Mazumder wrote this message on Fri, Oct 17, 2014 at 17:34 +0530: > > I am planning to use geom gate network for accessing remote disks. I set > up > > geom gate as per the freebsd handbook. I am using freebsd 9.2. > > I am noticing heavy performance impact for disk IO when using geom gate. > I > > am using the dd command to directly write to the SSD for testing > > performance. The IOPS gets cut down to 1/3 when accessing the SSD > remotely > > over a geom gate network, compared to the IOPS achieved when writing to > the > > SSD directly on the system where the SSD is attached. > > I thought that there might be some problems with the network, so decided > to > > create a geom gate disk on the same system where the SSD is attached. > This > > way the IO is not going over the network. However, in this use case I > > noticed the IOPS get cut down to 2/3 compared to IOPS achieved when > writing > > to the SSD directly. > > > > So, I have a SSD and its geom gate network disk created on the same node > > and the same IOPS test using the dd command gives 2/3 IOPS performance > for > > the geom gate disk compared to running the IOPS test directly on the SSD. > > > > This points to some performance issues with the geom gate itself. > > Not necessarily... Yes, it's slower, but at the same time, you now have > to run lots of network and TCP code in addition to the IO for each and > every IO... > > > Is anyone aware of any such performance issues when using geom gate > network > > disks? If so, what is the reason for such IO performance drop and are > there > > any solutions or tuning parameters to rectify the performance drop? > > > > Any information regarding the same will be highly appreciated. > > I did some work at this a while back... and if you're interested in > improving performance and willing to do some testing... I can send you > some patches.. > > There are a couple issues that I know about.. > > First, ggate specificly sets the buffer sizes, which disables the > autosizing of TCP's window.. This means that if you have a high latency, > high bandwidth link, you'll be limited to 128k / rtt of bandwidth. > > Second is that ggate isn't issueing multiple IOs at a time. This means > that any NCQ or tagging isn't able to be used, where as when running > natively they can be used... > > -- > John-Mark Gurney Voice: +1 415 225 5579 > > "All that I will do, has been done, All that I have, has not." > -- Sourish Mazumder 9986309755