From owner-freebsd-fs@FreeBSD.ORG Mon Mar 3 19:11:34 2014 Return-Path: Delivered-To: freebsd-fs@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 20CEBDB7 for ; Mon, 3 Mar 2014 19:11:34 +0000 (UTC) Received: from mail-lb0-x229.google.com (mail-lb0-x229.google.com [IPv6:2a00:1450:4010:c04::229]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 9C3F8FF8 for ; Mon, 3 Mar 2014 19:11:33 +0000 (UTC) Received: by mail-lb0-f169.google.com with SMTP id l4so4074650lbv.14 for ; Mon, 03 Mar 2014 11:11:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=pKw7Z8fOBnrEFXnAuO88NSVTtz2iXPTYL1NgnfcwZVs=; b=lIn2G6qf26B/4UtL0ORTOFwiJj1qts7bRXu73ThOxN6I5z99GL2n5zCppttG9X29ta l/5RGfO9U7O+MHw5rYkVGneJPNXNRs7wEFrQ8XcqmyLXDv/d9OpicFqabbuLP65vUdt5 JeQCmnYza1x2Q78RTh1UBJgAbqrdVyG+Z/hQMZjei0ckdW/6ajlpQxRZfbm/GBCTZAYv J0rwdM3uKHJeL5PXMBXZwW8PeXo5tIkg/Mc/KU88dbdSca9tBGTtukWnZMyF5vXQpIaE 627M6xo67Fa2D0Jt+4riS8DbIfe3il+Bq8jYZfpSligiXcz5zaB2HzVrx6ZUHmP1DlLj gV9Q== X-Received: by 10.112.140.202 with SMTP id ri10mr23119711lbb.9.1393873891095; Mon, 03 Mar 2014 11:11:31 -0800 (PST) Received: from localhost ([178.150.115.244]) by mx.google.com with ESMTPSA id sx1sm14255456lac.1.2014.03.03.11.11.29 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 03 Mar 2014 11:11:30 -0800 (PST) Date: Mon, 3 Mar 2014 21:11:28 +0200 From: Mikolaj Golub To: Andy D'Arcy Jewell Subject: Re: Is it feasible to run HAST with only ONE node long-term Message-ID: <20140303191127.GA9602@gmail.com> References: <20140303102248.6686617b@hyperion> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140303102248.6686617b@hyperion> User-Agent: Mutt/1.5.22 (2013-10-16) Cc: freebsd-fs@FreeBSD.org X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 03 Mar 2014 19:11:34 -0000 On Mon, Mar 03, 2014 at 10:22:48AM +0000, Andy D'Arcy Jewell wrote: > My main worry is that HAST performance might suffer as the delta grows > between the master and it's long-lost slave; does the master > consume extra resources (memory, disk) "saving up" the replication > stream objects, or does it just rely on a time/version stamp so when > (in normal operation) the slave gets back in contact with the master, > it knows to do a full sync? No performance degradation is expected. hastd(8) maintains a map of dirty extents. The map size is static, just more blocks are marked as dirty during disconnect. It would only affect synchronization time after the connection is restored. You might consider setting the remote address to "none" (see hast.conf(5)) to make hastd(1) even not try to connect to the secondary. -- Mikolaj Golub