From owner-freebsd-fs@FreeBSD.ORG Fri Dec 2 20:15:15 2011 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5A569106564A for ; Fri, 2 Dec 2011 20:15:15 +0000 (UTC) (envelope-from bfriesen@simple.dallas.tx.us) Received: from blade.simplesystems.org (blade.simplesystems.org [65.66.246.74]) by mx1.freebsd.org (Postfix) with ESMTP id 203288FC08 for ; Fri, 2 Dec 2011 20:15:14 +0000 (UTC) Received: from freddy.simplesystems.org (freddy.simplesystems.org [65.66.246.65]) by blade.simplesystems.org (8.14.4+Sun/8.14.4) with ESMTP id pB2KF5PB002648; Fri, 2 Dec 2011 14:15:05 -0600 (CST) Date: Fri, 2 Dec 2011 14:15:05 -0600 (CST) From: Bob Friesenhahn X-X-Sender: bfriesen@freddy.simplesystems.org To: Jason Hellenthal In-Reply-To: <20111202200241.GA38979@DataIX.net> Message-ID: References: <4ED8D7A5.7090700@icritical.com> <4ED8EC9A.2080706@icritical.com> <20111202200241.GA38979@DataIX.net> User-Agent: Alpine 2.01 (GSO 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.2 (blade.simplesystems.org [65.66.246.90]); Fri, 02 Dec 2011 14:15:05 -0600 (CST) Cc: freebsd-fs@freebsd.org Subject: Re: Monitoring ZFS IO X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 02 Dec 2011 20:15:15 -0000 On Fri, 2 Dec 2011, Jason Hellenthal wrote: >>> >>> I want to see how many bytes or KB have been read and written to a given >>> zpool since creation (as in the newer of uptime or zpool creation) on the >>> system. >> >> This implies that these statistics would need to be stored in the pool >> itself, which implies that the statistics need to be periodically >> written (e.g. in each transaction group) as a form of metadata. >> > > I thought this was ( df -[h,b,m,g]) output... ;) Apparently the term "creation" was meant to mean "since boot" rather than since filesystem creation. Regardless, it is possible to write thousands of times more data to a filesystem than it contains. This means that 'df' won't do the job. It would be nice if the zfs pool could store its own performance data since the dawn of time. Bob -- Bob Friesenhahn bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/