From owner-freebsd-doc@FreeBSD.ORG Sat Dec 3 22:20:06 2005 Return-Path: X-Original-To: freebsd-doc@hub.freebsd.org Delivered-To: freebsd-doc@hub.freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2977216A41F for ; Sat, 3 Dec 2005 22:20:06 +0000 (GMT) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [216.136.204.21]) by mx1.FreeBSD.org (Postfix) with ESMTP id 158FA43D5E for ; Sat, 3 Dec 2005 22:20:03 +0000 (GMT) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (gnats@localhost [127.0.0.1]) by freefall.freebsd.org (8.13.3/8.13.3) with ESMTP id jB3MK2Pn001160 for ; Sat, 3 Dec 2005 22:20:02 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.13.3/8.13.1/Submit) id jB3MK2qI001159; Sat, 3 Dec 2005 22:20:02 GMT (envelope-from gnats) Resent-Date: Sat, 3 Dec 2005 22:20:02 GMT Resent-Message-Id: <200512032220.jB3MK2qI001159@freefall.freebsd.org> Resent-From: FreeBSD-gnats-submit@FreeBSD.org (GNATS Filer) Resent-To: freebsd-doc@FreeBSD.org Resent-Reply-To: FreeBSD-gnats-submit@FreeBSD.org, Lowell Gilbert Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 353D716A41F for ; Sat, 3 Dec 2005 22:13:49 +0000 (GMT) (envelope-from lowell@be-well.ilk.org) Received: from mail22.sea5.speakeasy.net (mail22.sea5.speakeasy.net [69.17.117.24]) by mx1.FreeBSD.org (Postfix) with ESMTP id D7D6F43D62 for ; Sat, 3 Dec 2005 22:13:48 +0000 (GMT) (envelope-from lowell@be-well.ilk.org) Received: (qmail 2241 invoked from network); 3 Dec 2005 22:13:48 -0000 Received: from dsl092-078-145.bos1.dsl.speakeasy.net (HELO be-well.ilk.org) ([66.92.78.145]) (envelope-sender ) by mail22.sea5.speakeasy.net (qmail-ldap-1.03) with SMTP for ; 3 Dec 2005 22:13:47 -0000 Received: by be-well.ilk.org (Postfix, from userid 1147) id CCBC42841D; Sat, 3 Dec 2005 17:13:46 -0500 (EST) Message-Id: <20051203221346.CCBC42841D@be-well.ilk.org> Date: Sat, 3 Dec 2005 17:13:46 -0500 (EST) From: Lowell Gilbert To: FreeBSD-gnats-submit@FreeBSD.org X-Send-Pr-Version: 3.113 Cc: Subject: docs/89900: [PATCH] new text on backup strategies for Handbook X-BeenThere: freebsd-doc@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Documentation project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 03 Dec 2005 22:20:06 -0000 >Number: 89900 >Category: docs >Synopsis: [PATCH] new text on backup strategies for Handbook >Confidential: no >Severity: non-critical >Priority: medium >Responsible: freebsd-doc >State: open >Quarter: >Keywords: >Date-Required: >Class: change-request >Submitter-Id: current-users >Arrival-Date: Sat Dec 03 22:20:02 GMT 2005 >Closed-Date: >Last-Modified: >Originator: Lowell Gilbert >Release: FreeBSD 6.0-STABLE i386 >Organization: n/a >Environment: System: FreeBSD be-well.ilk.org 6.0-STABLE FreeBSD 6.0-STABLE #5: Tue Nov 29 19:56:53 EST 2005 root@be-well.ilk.org:/usr/src/sys/i386/compile/BE-WELL6 i386 >Description: This is new text discussing how to choose backup strategies. >How-To-Repeat: n/a >Fix: --- en_US.ISO8859-1/books/handbook/disks/chapter.sgml.ORIG Fri Aug 5 15:06:20 2005 +++ en_US.ISO8859-1/books/handbook/disks/chapter.sgml Sat Dec 3 16:03:31 2005 @@ -2269,8 +2269,103 @@ restore it, even if you have not asked it to! + + Backup Strategies + + + The first requirement in devising a backup plan is to make sure that all of the + following problems are covered: + + + + disk failure + + + + + accidental file deletion + + + + + random file corruption + + + + + complete machine destruction (e.g., fire) including destruction of any on-site backups + + + + + It is perfectly possible that some systems will be best served by + having each of these problems covered by a completely different + technique. Except for strictly personal systems with very low-value + data, it is unlikely that one technique would cover all of them. + + Some of the techniques in the toolbox are: + + + archives of the whole system, backed up onto permanent media + offsite. This actually provides protection against all of the + possible problems listed above, but is slow and inconvenient to + restore from. You can keep copies of the backups onsite and/or + online, but there will still be inconveniences in restoring files, + especially for non-privileged users. + + + + filesystem snapshots. This is really only helpful in the + accidental file deletion scenario, but it can be + very helpful + in that case, and is quick and easy to deal with. + + + + + copies of whole filesystems and/or disks. [for example, + periodic rsync of the whole machine] This is generally most + useful in networks with unique requirements. For general + protection against disk failure, it is usually inferior to + RAID. For restoring accidentally deleted + files, it can be comparable to UFS + snapshots, but that depends on your preferences. + + + + + + RAID. Minimizes or avoids downtime + when a disk fails. At the expense of having to deal with disk + failures more often (because you have more disks), albeit at a + much lower urgency. + + + + + + checking fingerprints of files. The + &man.mtree.8; + program is very useful for this. Although it is not a backup + technique, it helps guarantee that you will notice when you need + to resort to your backups. This is particularly important for + offline backups, and should be checked periodically. + + + + + It is quite easy to come up with even more techniques, many of them + variations on the ones listed above. Specialized requirements will + usually lead to specialized techniques (for example, backing up a live + database usually requires a method particular to the database + software as an intermediate step). The important thing is to know + what dangers you want to protect against, and how you will handle + each. + + + Backup Basics The three major backup programs are >Release-Note: >Audit-Trail: >Unformatted: