From owner-freebsd-questions@FreeBSD.ORG Wed May 7 00:25:54 2014 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 38D4990D for ; Wed, 7 May 2014 00:25:54 +0000 (UTC) Received: from mail-lb0-x234.google.com (mail-lb0-x234.google.com [IPv6:2a00:1450:4010:c04::234]) (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 B55DD811 for ; Wed, 7 May 2014 00:25:53 +0000 (UTC) Received: by mail-lb0-f180.google.com with SMTP id p9so303170lbv.39 for ; Tue, 06 May 2014 17:25:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type:content-transfer-encoding; bh=v3hKLeDIVOQHKMy1xy1a8DeQIosaNP+tiZQnB+PQe2c=; b=TUPLawZU/GhckjeRtkUKQkItx91Tudv7c6b8Fhg3rul835RmU41gBeM6E3xD06Estq W+uVu+q0yHYbIAq3hyGe4UQ7uD/FJuxXzuZBB/ppmcA6CLCr4/yT+Q3pXsTmHiiSFEOR kro9mVpIkRR64RWA4mjaRvFvsb9EpdHzEOhzcrVFwWC3gOigSwykT+LpsbCDy+2qNXLM nsagguukd3tydXbKfUtWZfOawS19Vcvq3za1XScWhsvqE/aZa7KHLq6C9CBQQdTe/ZXN zZ1iNwhlVuv+nOtP+CZcr0ErWNtGqnDggyfJCDk1ZPefCdoesxkqZ6FDJsCrXzzqrqQi a0bQ== X-Received: by 10.112.199.234 with SMTP id jn10mr11280054lbc.8.1399422351241; Tue, 06 May 2014 17:25:51 -0700 (PDT) Received: from lazlar.no-ip.biz (109.58.144.242.bredband.tre.se. [109.58.144.242]) by mx.google.com with ESMTPSA id xa9sm154863lbb.36.2014.05.06.17.25.49 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 06 May 2014 17:25:50 -0700 (PDT) Message-ID: <53697D8B.2060906@gmail.com> Date: Wed, 07 May 2014 02:25:47 +0200 From: Rolf Nielsen User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: freebsd-questions@freebsd.org Subject: Re: Swap on ZFS References: In-Reply-To: X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 07 May 2014 00:25:54 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 2014-05-06 21:21, David Noel wrote: > Is swap on ZFS still ill-advised? All the forum, list, and blog > posts I find say it's a no-go. Is this still the case? The idea > behind it not working is that ZFS needs memory to write to disk, so > when you need to swap (are low on memory) ZFS won't be able to > write. > > I found some talk of having a tunable added as a workaround that > would reserve a certain amount of memory for ZFS so this wouldn't > be a problem, but have no idea if anyone's made any progress > towards implementing it. Just out of curiosity, why do you want it? To get swap on ZFS, you first need to create a ZFS filesystem on one or more devices, then you create a dedicated volume inside that filesystem and use that dedicated volume as swap. To me that seems to add unnecessary complexity, similar to using a file backed md device as swap. Please don't take this as criticism; you may very well have good reasons for wanting to do this. I'm just curious about those reasons. Rolf Nielsen -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (FreeBSD) iQIcBAEBAgAGBQJTaX2LAAoJEB1OKfQ0M8Tg+zEQAMvhXbgl8/LE2s9ltfvfbnGe bMnBmYxMekQiZ14+n2467nP6z0OCr5AM/W53GxQ9ma2M9AkuU6WKr+srv1pe2eck cLnMA3EekiYLuDle5I2+Kc2NjZ/lVAVl379vYmzRGFbU2Uke2aZtgyQ9kUB+vrfl TeJ8QwmIDcCPELIDZJzI+WqLJZqDY2HfcWs5WtJkqqGf+27tYmS4aAFYWZQv7hFE K5Ps798LFQHshhAxqoWmOLbeeDhCSAsaOIMyIknPJ1I9xyXh2BDP16yRj37mw8Yk 7ca84uqQ5e0HJ6lhEU/RXc4kKuNKUDYZNB7d4jKNOBpDbx5irCJVAnAcdu/YD9G0 P7GpDd8RJR1EUmH32zTSmZnieoTtQNBcbxQo+pFVEi52yX6Q9GVwPkJfh4gjdiE/ 1JtWFhCSxGeBjjZlaTAntyA+YjRgiXM1cK3DbBeigc4LQtm4Ztoz2DsgxR70pE0x Fthliso+NSUZiz1rE9ep8Wc+4bIYzqfX+KI0PBz83V2ytpYEs1iNNm3au9sGyqib f6t2z1I0o8XO75CGlQjA1lEulKeY4cnpr948QCZMdKLzUd+DiyuF+qzZvOlGlQ3A QNz4/pSNXlZ48bK7R7C3u9xbRxqluJ58BUf3B6hu4wkgc6DqAWOxoWBGLck/dqfa XiUZqUred6DdnTzAXxXM =8BGL -----END PGP SIGNATURE-----