From owner-freebsd-questions@FreeBSD.ORG Sat Oct 2 09:30:47 2010 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 55DC4106564A for ; Sat, 2 Oct 2010 09:30:47 +0000 (UTC) (envelope-from amsibamsi@gmail.com) Received: from mail-ey0-f182.google.com (mail-ey0-f182.google.com [209.85.215.182]) by mx1.freebsd.org (Postfix) with ESMTP id DB17F8FC14 for ; Sat, 2 Oct 2010 09:30:46 +0000 (UTC) Received: by eyx24 with SMTP id 24so1780634eyx.13 for ; Sat, 02 Oct 2010 02:30:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from :user-agent:mime-version:to:subject:x-enigmail-version:content-type :content-transfer-encoding; bh=Kml7e4QiyU3KkQEuXDpMG0+h32THrfKl1SvSMbT0JMA=; b=t/9BV/J0vIIBQqgtNnIc75Ldoo/eUyOzFy8+2BQ8IZgRLoT+wl1CakVGNK/OIn2z5X zBuKwZKK2Hm+tb2ncWGh/uGMXO2TY+YkJBTmCVSASi0vFeUCud6AkmnPCM9cKeJjI4Ix fVb+yHSkfDJgr/qhQi1M9K+mykzS++ihbxPoA= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:subject :x-enigmail-version:content-type:content-transfer-encoding; b=CEaMf3vwsW5YvhHPNLiNDfvQzEw4XflaOZ1BGY0kQPL0zbkTIHsMxBbU7ki+2WIphw DwchhGQk/Oy0vFST2Ax+g4hixjMyuabpcaBpARp17xXrcT2zRvBOSFgQ2ZtldCYfYcm/ 36J/gNfZACQ9QIHe3w07nyGp0cyFwZJqKdwDs= Received: by 10.213.108.73 with SMTP id e9mr6475443ebp.36.1286011845883; Sat, 02 Oct 2010 02:30:45 -0700 (PDT) Received: from hulk.l.ttyv0.net (80-219-18-72.dclient.hispeed.ch [80.219.18.72]) by mx.google.com with ESMTPS id u9sm3343199eeh.23.2010.10.02.02.30.44 (version=SSLv3 cipher=RC4-MD5); Sat, 02 Oct 2010 02:30:44 -0700 (PDT) Message-ID: <4CA6FBC2.8080908@gmail.com> Date: Sat, 02 Oct 2010 11:30:42 +0200 From: Anselm Strauss User-Agent: Mozilla/5.0 (X11; U; FreeBSD amd64; en-US; rv:1.9.1.11) Gecko/20100723 Thunderbird/3.0.6 MIME-Version: 1.0 To: freebsd-questions@freebsd.org X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Swap on ZFS 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: Sat, 02 Oct 2010 09:30:47 -0000 Hi I have a virtual server with only 512 MB of memory but still want to run ZFS on it. When there is IO load and only few memory left it occasionally happens that the server freezes, network ping will still work. As far as I know there was the problem that an IO request on ZFS first needs to allocate some memory before it can be run. So in the case where no memory is left and some swap must be used which lies also on ZFS, it would still first need some free memory for the request. This basically results in a deadlock and the system freezes. Would this not happen every time when the system is out of memory and swap must be used? So it basically makes swap on ZFS useless. Has there been any fix or workaround for this? I guess it does not help when I use a swap file on ZFS instead of a separate zvol. Appreciating any ideas Anselm