From owner-freebsd-questions@FreeBSD.ORG Wed Jan 21 04:17:53 2009 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 4E029106564A for ; Wed, 21 Jan 2009 04:17:53 +0000 (UTC) (envelope-from dan@dan.emsphone.com) Received: from email1.allantgroup.com (email1.emsphone.com [199.67.51.115]) by mx1.freebsd.org (Postfix) with ESMTP id 08A8B8FC16 for ; Wed, 21 Jan 2009 04:17:52 +0000 (UTC) (envelope-from dan@dan.emsphone.com) Received: from dan.emsphone.com (dan-a.emsphone.com [199.67.51.107]) by email1.allantgroup.com (8.14.0/8.14.0) with ESMTP id n0L4Ho6c039690 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Tue, 20 Jan 2009 22:17:50 -0600 (CST) (envelope-from dan@dan.emsphone.com) Received: from dan.emsphone.com (smmsp@localhost [127.0.0.1]) by dan.emsphone.com (8.14.3/8.14.3) with ESMTP id n0L4HntG052007 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Tue, 20 Jan 2009 22:17:49 -0600 (CST) (envelope-from dan@dan.emsphone.com) Received: (from dan@localhost) by dan.emsphone.com (8.14.3/8.14.3/Submit) id n0L4HlFc051952; Tue, 20 Jan 2009 22:17:47 -0600 (CST) (envelope-from dan) Date: Tue, 20 Jan 2009 22:17:47 -0600 From: Dan Nelson To: Geoff Fritz Message-ID: <20090121041747.GD45931@dan.emsphone.com> References: <20090120235256.GB30866@dev.null> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090120235256.GB30866@dev.null> X-OS: FreeBSD 7.1-STABLE User-Agent: Mutt/1.5.18 (2008-05-17) X-Virus-Scanned: ClamAV version 0.94.1, clamav-milter version 0.94.1 on email1.allantgroup.com X-Virus-Status: Clean X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-2.0.2 (email1.allantgroup.com [199.67.51.78]); Tue, 20 Jan 2009 22:17:50 -0600 (CST) X-Scanned-By: MIMEDefang 2.45 Cc: freebsd-questions@freebsd.org Subject: Re: Way to prune/limit the ZFS zpool history? 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: Wed, 21 Jan 2009 04:17:53 -0000 In the last episode (Jan 20), Geoff Fritz said: > I've been experimenting with a series scripts that takes ZFS > snapshots every minute, eventually destroying the oldest so that only > so many remain available for a given window of time. > > This may seem a trivial concern with hard drive sizes being what they > are these days, but after running a "zpool history" I started > thinking that a ZFS create and destroy being performed every minute > would add up to a lot over the course of a few years (current > estimate is 62MB/year for the naming scheme of my snapshots). According to http://docs.sun.com/app/docs/doc/819-5461/gdswe?l=en&a=view , the zpool history file is between 128K and 32MB, depending on the size of the pool. The FreeBSD import at /sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_history.c agrees with the docs :) -- Dan Nelson dnelson@allantgroup.com