From owner-freebsd-stable@freebsd.org Mon Jun 18 12:45:34 2018 Return-Path: Delivered-To: freebsd-stable@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 25EB51004E23; Mon, 18 Jun 2018 12:45:34 +0000 (UTC) (envelope-from amvandemore@gmail.com) Received: from mail-io0-x243.google.com (mail-io0-x243.google.com [IPv6:2607:f8b0:4001:c06::243]) (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 9C8757D17C; Mon, 18 Jun 2018 12:45:33 +0000 (UTC) (envelope-from amvandemore@gmail.com) Received: by mail-io0-x243.google.com with SMTP id g22-v6so16675854iob.7; Mon, 18 Jun 2018 05:45:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=X7GGfWcpVoVkltKL5FQgGVyHe5nBeav5QBdJBYf5Hbg=; b=hvCOLjVg8sf04QLwK0lah8XaNZmWj/sB7vt3pYT1ibBcu0ljGywJbTQ453Eeg9Elb8 peF2lf2krwVzMUaMhiUkANXFjrMcHg4cWtFl+z6DF7Y7TpViNv7kzdn/6BIzMTvzoqyR vRku5KrTRjPoftMB3OlcLcMOQ7TGss7T/Kgt6KqgVXXU6IkIw6SJy9mAIQwjc4eyZ267 OCZ5uSIVAmuCONnbfmjbMd71JhnXlySqz6kH1J3OoErI8UlQ/kMoNs5G2MTRS59QugUi bFDKF9a4nX2e4pCfhpEvHCzWzi63IuAqndYuBfZSqfcEPnagJvwVAtABLtFnhpjPlTiR U8Qw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=X7GGfWcpVoVkltKL5FQgGVyHe5nBeav5QBdJBYf5Hbg=; b=PyKMKHkn3CLaUXpD3um9/ZlRSkJeDtCF92wCk8ye5O4wRYJMYK555MgBuz7tfl83p+ xuYrQt6uokWdIsnyEJjTzxG1yAzH92EBXbs7zVl1xx0t5gdURTfQMb/dMpXNpHiFqpkl +sAYS6s963NJC3kJcNMCtETOwAHNk164fJvl6NkJ4o9NKvPfhpGsru+klXjcGqFfRAue 57E/GTmAotcqtaBPAMlhz26J/eVz96MNpDyhLiwJ5PHKOcXe7hgM5SHPsbIWqTGHASbn 4kTmfwg4vaDtYCrgZq8vnhWZILnc8bTjKsq4OWUXVQCOJzEuwigYAdP4UbSIF5U54Tf0 s50Q== X-Gm-Message-State: APt69E3r4wfcKPjlLpUngS/WDUviKK54VP381klPp/GQflw6XVE5Nv5h yOYLHX3voej7SdNR0z7MROq63L8tjtkaQAK+nSfOYA== X-Google-Smtp-Source: ADUXVKK6XbjnWFwax0NwrI/K15cppRA/3unysjKncozVFqZ5uGYX/pkygBZLm9wiuVP93at4CPSfqnth/UJ74IYZnhk= X-Received: by 2002:a6b:b48b:: with SMTP id d133-v6mr9551268iof.26.1529325932813; Mon, 18 Jun 2018 05:45:32 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a02:8d5c:0:0:0:0:0 with HTTP; Mon, 18 Jun 2018 05:45:31 -0700 (PDT) In-Reply-To: References: <20180618160855.44d9a0c2.freebsd.ed.lists@sumeritec.com> From: Adam Date: Mon, 18 Jun 2018 07:45:31 -0500 Message-ID: Subject: Re: lightly loaded system eats swap space To: tech-lists Cc: "freebsd-stable@freebsd.org" , FreeBSD Questions Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.26 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 18 Jun 2018 12:45:34 -0000 On Mon, Jun 18, 2018 at 7:27 AM, tech-lists wrote: > On 18/06/2018 09:08, Erich Dollansky wrote: > >> Hi, >> >> On Sun, 17 Jun 2018 23:19:02 +0100 >> tech-lists wrote: >> >> freebsd-11-stable r333874, ZFS raidz1-0 (3x4TB disks), 128GB RAM, >>> Swap: 4096M Total, 3502M Used, 594M Free, 85% Inuse >>> >> >> this might not be related but I noticed that your swap space is small >> compared to RAM size. I noticed on a much smaller Raspberry Pi, that it >> runs into trouble when there is no swap even there is enough RAM >> available. Is it easily possible for you to add some GB of swap space >> and let the machine run then? >> >> How much swap do the other machines have? >> > > Hi, > > Yes, the machine with the problem uses the default 4GB swap. That's all > the swap it has. The machine without issue has a swapfile installed on a > SSD in addition to the default 4GB swap. > > problematic machine: > Device 512-blocks Used Avail Capacity > /dev/ada0p3 8388608 3.3G 714M 83% > > machine without a problem, it has swapfile installed: > Device 512-blocks Used Avail Capacity > /dev/ada0s1b 8262248 1.7G 2.2G 44% > /dev/md0 65536000 1.9G 29G 6% > Total 73798248 3.7G 32G 10% > > I added the swapfile a long time ago on this machine due to the same issue. > > But my problem isn't so much an out of swapspace problem; all this is, is > a symptom. My problem is "why is it swapping out at all on a 128GB system > and why is what's swapped out not being swapped back in again". > What is the output of sysctl vm.overcommit? If this system is intended on being a VM host, then why don't you limit ARC to something reasonable like Total Mem - Projected VM Mem - Overhead = Ideal ARC . -- Adam