From owner-freebsd-questions@freebsd.org Thu Sep 24 16:40:31 2015 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 4C858A05C60 for ; Thu, 24 Sep 2015 16:40:31 +0000 (UTC) (envelope-from quartz@sneakertech.com) Received: from douhisi.pair.com (douhisi.pair.com [209.68.5.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 2F0921268 for ; Thu, 24 Sep 2015 16:40:30 +0000 (UTC) (envelope-from quartz@sneakertech.com) Received: from [10.2.2.1] (pool-173-48-121-235.bstnma.fios.verizon.net [173.48.121.235]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by douhisi.pair.com (Postfix) with ESMTPSA id A26F23F78E for ; Thu, 24 Sep 2015 12:40:24 -0400 (EDT) Message-ID: <56042774.6070404@sneakertech.com> Date: Thu, 24 Sep 2015 12:40:20 -0400 From: Quartz MIME-Version: 1.0 To: FreeBSD questions Subject: sync vs async vs zfs Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 Sep 2015 16:40:31 -0000 I'm trying to spec out a new system that looks like it might be very sensitive to sync vs async writes. However, after some research and investigation I've come to realize that I don't think I understand a/sync as well as I thought I did and might be confused about some of the fundamentals. Can someone point me to a good "newbie's guide" that explains sync vs async from the ground up? one that makes no assumptions about prior knowledge of filesystems and IO. And likewise, another guide specifically for how they relate to zfs pool/vdev configuration? Thanks in advance.