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-CVS Best Practices - - - - -Vivek -Venugopalan - -
&MYEMAIL;
 - - - - - -0.7 -2005-10-15 -vv -A bunch of minor fixes as suggested by readers. - - - -0.6 -2002-09-10 -vv -Added content related to tagging and daily builds. Changed -Linuxdoc URLs to tldp. Fixed stale links and added other corrections -suggested by readers. - - - -0.5 -2002-08-25 -vv -Fixed some more errors in the document and added references to -other CVS sources and some server side scripting - - - -0.4 -2002-03-10 -vv -Added new email address, Added an example flow to show how the -practices help - - - -0.3 -2001-12-06 -vv -Grammatical errors cleanup - - - -0.2 -2001-11-27 -vv -Incorporated first round of feedback and -some minor fixes - - -0.1 -2001-11-20 -vv -Created - - - - - - - -CVS Best Practices - -This article explores some of the best practices that can be adopted -while using CVS as the configuration management tool in your software -projects. - - - - -Introduction - -
-Henry David Thoreau (1817-1862) - -Men have become the tools of their tools. - -
- -This article outlines some of the best practices that can be adopted -when &CVS; is used as the configuration management tool in your software -project. - - -&CVS; (&CVSAB;) is an &OPENSOURCE; configuration management -tool that is now being looked at seriously by many commercial organizations as -a viable alternative to other commercial &SCM; tools. - -This spotlight on &CVSAB; has led to the inevitable question of best -practices for deploying &CVSAB; as the backbone &SCMAB; tool for large -software development projects. Having answered this question many times -verbally as a bunch of gotchas on &CVSAB;, it was time to put -down on paper some of the best practices that will work well for -&CVSAB; based projects. - - This paper assumes that the reader is familiar with the -fundamentals of software version control. Including features like -branching, merging, tagging (labelling) etc., offered by modern version -control tools such as &CVSAB; - -Further, This paper is not an introduction to &CVSAB; and its usage. There are -excellent articles available on the net for the same. This paper assumes -that the reader is familiar with &CVSAB; commands and is looking at -deploying &CVSAB; in his or her organization. Some of the popular -&CVSAB; related links that can provide &CVSAB; education are. - - - -The &CVS; site where -current informaton about CVS is available. Including the &CVSAB; manual. - - - -Karl Fogel's book, Open Source Development with -CVS is available online. - - - - - - - - -Copyright Information - - This document is Copyright © 2001 Vivek Venugopalan. Permission -is granted to copy, distribute and/or modify this document under the terms of -the GNU Free Documentation -License, Version 1.1 or any later version published by the -Free Software Foundation with no Invariant Sections, no Front-Cover Texts, and -no Back-Cover Texts. A copy of the license can be found in . - - This document may be reproduced and distributed in whole or in part, in -any medium physical or electronic, as long as this copyright notice is -retained on all copies. Commercial redistribution is allowed and encouraged; -however, the author would like to be notified of any such distributions. - - - All translations, derivative works, or aggregate works incorporating -this document must be covered under this copyright notice. That is, you may -not produce a derivative work from this document and impose additional -restrictions on its distribution. Exceptions to these rules may be granted -under certain conditions; please contact the author at the address given -below. - - In short, we wish to promote dissemination of this information through -as many channels as possible. However, we do wish to retain copyright on the -document, and would like to be notified of any plans to redistribute the same. - - - - - Disclaimer - - No liability for the contents of this document can be accepted. Use -the concepts, examples and other content at your own risk. As this is a new -edition of this document, there may be errors and inaccuracies that may of -course be damaging to your system. Proceed with caution, and although this is -highly unlikely, the author(s) do not take any responsibility whatsoever. - - - All copyrights are held by their respective owners, unless specifically -noted otherwise. Use of a term in this document should not be regarded as -affecting the validity of any trademark or service mark. - - Naming of particular products or brands should not be seen as -endorsements. - - You are strongly recommended to take a backup of your system before -major installation and backups at regular intervals. - - - - -New Versions - - This document is Version : &DOCVERSION;. - - The latest version of this document can be obtained from (In the order of latest version availability) - - - - -My website - - - - -The linux documentation project - - - - - - - - -Credits -The list of people who have provided information and correction for this -paper in no particular order are. - - - Jens-Uwe Mager - Jorgen Grahn - Thomas S. Urban - Cam Mayor - Sally Miller - Niels Jakob Darger - - - - - - - -Feedback - - Feedback is most certainly welcome for this document. Without your -submissions and input, this document wouldn't exist. Please send your -additions, comments and criticisms to the following email address : -&MYEMAIL;. - - - - - - -Focus Areas -The focus areas for best practice are - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Using <acronym>GUI</acronym> Tools - -The traditional interface available for CVS is the command-line client. -There has also been a slew of GUI client applications that can -talk to a &CVSAB; server. These GUI clients provide a -point and click interface to the &CVSAB; repository. - - - -§ion2-useguiclient; - - This paper recommends using such GUI clients during the initial -deployment of &CVSAB; in an organization. - -Developers typically use integrated development environments that have -the CM tools integrated into them. These tools minimize the learning for the -developers about the intricacies of &CVSAB; usage and instead allow them to be -productive from day one. Developers who are accustomed to other CM tools will -find the &CVSAB; command-line interface daunting. The adoption and usage of -&CVSAB; can be improved by using GUI tools for &CVSAB; clients. - - GUI tools for &CVSAB; are available at http://cvsgui.sourceforge.net/. -GUI interfaces are available for most of the popular platforms (Windows, Mac -and Linux). In addition, on the Windows platform there is an -SCC extension that allows integration of &CVSAB; as the -configuration control tool with popular IDE. - - - - - - - -§ion1-devsandbox; - -The developer sandbox is where each developer keeps his -or her working copy of the code base. In &CVSAB; this is referred to as the -working directory. This is where they build, test and debug the modules that -they are working on. A sandbox can also be the area where the staging build -or the production build is done. Changes made in the work area are checked -into the &CVSAB; repository. In addition, changes made in the repository by -others have to be updated in the sandbox on a regular basis. - -The best practices related to developers sandbox are: - - - -§ion2-clockinsync; -&CVSAB; tracks change to source files by using the timestamp on the -file. If each client system date and time is not in sync, there is a -definite possibility of &CVSAB; getting confused. Thus system clocks must be -kept in sync by use of a central time server or similar mechanism. - - -&CVSAB; is designed from ground up to handle multiple timezones. As -long as the host operating system has been setup and configured correctly, -&CVSAB; will be able to track changes correctly. - - - - - -§ion2-dontshare; - -Sandboxes have to be unique for each developer or purpose. They -should not be used for multiple things at the same time. A sandbox can be a -working area for a developer or the build area for the final release. If -such sandboxes are shared, then the owner of the sandbox will not be aware -of the changes made to the files resulting in confusion. - -In &CVSAB;, the sandbox is created automatically when a working copy is -checked out for a &CVSAB; project using the cvs checkout -{project-name} command. - -In very large projects, it does not make sense for the developers to -check-out the entire source into the local sandbox. In such cases, they can -take the binaries generated by the build team on a regular basis for all those -components of the application that is not changed by them and only check-out -the parts that are built by the developer. - -For example, in a Java project, the build team can keep the results of -their last successful build in a standard location in the form of JAR files on -the network file servers. Individual developers will use a standard classpath -setup that has the network drives mounted on standard paths. Thus, the -developers will automatically get the latest version of the files as required -by them. - - - - -§ion2-syncup; - -To gain the benefits of working within a sandbox as mentioned above, -the developer must keep his or her sandbox in sync with the main repository. -A regular cvs update with the appropriate tag or branch -name will ensure that the sandboxes are kept up to date. - - - - -§ion2-workinside; - -The sandbox can be thought of as a controlled area within which &CVSAB; - can track for changes made to the various source files. Files belonging to - other developers will be automatically updated by &CVSAB; in the developer's - sandbox. Thus the developer who lives within the sandbox will stand to gain - a lot of benefits of concurrent development. - - - - - -§ion2-cleanupatcompletion; - -Make sure that the sandbox is cleaned up after completion of work on -the files. Cleanup can be done in &CVSAB; by using the cvs -release command. This ensures that no old version of the files -exists in the development sandbox. As explained previously, pre-built -binaries from the build team can be used to ensure that all the parts of the -application are available to the developer without the need for a complete -compilation in the sandbox. - - - - -§ion2-checkin; - -To help other developers keep their code in sync with your code, you -must check-in your code often into the &CVSAB; repository. The best -practice would be to check-in soon as a piece of code is completed, reviewed -and tested, check-in the changes with cvs commit to -ensure that your changes are committed to the &CVSAB; repository. - - &CVSAB; promotes concurrent development. Concurrent development is -possible only if all the other developers are aware of the ongoing changes -on a regular basis. This awareness can be termed as situation -awareness - - One of the bad practices that commonly occur -is the sharing of files between developers by email. This works against -most of the best practices mentioned above. To share updates between two -developers, &CVSAB; must be used as the communication medium. This will -ensure that &CVSAB; is aware of the changes and can track -them. Thus, audit trail can be established if necessary. - - - - - - -§ion1-serverconfig; -This section deals with best practices for &CVSAB; server side setup and -configuration. - - - - §ion2-accesscontrol; - - One of the important questions that I have been asked time and again is the - ability to have access control for files/folders/branches etc., within - the &CVSAB; repository for various users. Unfortunately &CVSAB; does not - come with a built in Access control capability but it does support a - rudimentary form of access control through the readers/writers files in - the CVSROOT repository. I have put together a set of scripts that use - the readers/writers files to provide a slightly useable version of access - control. This is available at http://cvspermissions.sarovar.org - as an &OPENSOURCE; project. Feel free to use it and let me know how it - works for you. - - - §ion2-scripting; - -Server side scripting refers to the ability to make &CVSAB; server - execute certain scripts when an event occurs. A common script that - helps is to verify that all cvs commits contain acomment entered by the - developer. The process involves setting up the - CVSROOT/verifymsg file to run a script when a file is - checked-in. - - -------CVSROOT/verifymsg--------- - -#Set the verifymsg file to fire a script -DEFAULT /usr/local/bin/validate-cvs-log.sh - - -------/usr/local/bin/validate-cvs-log.sh --------- - -#!/bin/sh -# -# validate-cvs-log.sh logfile - -# test that log message has some characters in it -if [ `cat $1 | wc -c ` -lt 10 ] ; then -echo "log message too short; please enter a description for the changes" - exit 1 -else - exit 0 -fi - - - - - -§ion2-notification; - -The &CVSAB; server can be configured to notify through e-mails in case -of a commit happening. This can be used to verify whether commits are -occurring during the course of a daily/release build. If such commits -occur, based on the project policy, the commits can be ignored or the entire -build automatically restarted. - - - - - - - -§ion1-branchmerge; - - Branching in &CVSAB; splits a project's development into separate, -parallel histories. Changes made on one branch do not affect the other -branches. Branching can be used extensively to maintain multiple versions -of a product for providing support and new features. - - Merging converges the branches back to the main trunk. In a merge, -CVS calculates the changes made on the branch between the point where it -diverged from the trunk and the branch's tip (its most recent state), then -applies those differences to the project at the tip of the trunk. - - -§ion2-branchowner; - -The main trunk of the source tree and the various branches should have a -owner assigned who will be responsible for. - - - - -Keep the list of configurable items for the branch or trunk. - - -The owner will be the maintainer of the contents list for the branch or -trunk. This list should contain the item name and a brief description about -the item. This list is essential since new artifacts are always added to or -removed from the repository on an ongoing basis. This list will be able to -track the new additions/deletions to the repository for the respective branch. - - - - - -Establish a working policy for the branch or trunk. - - -The owner will establish policies for check-in and check-out. The -policy will define when the code can be checked in (after coding or after -review etc.,). Who is responsible to merge changes on the same file and -resolve conflicts (the author or the person who recently changed the file). - - - - - -Identify and document policy deviations - - -Policies once established tend to have exceptions. The owner will be -responsible for identifying the workaround and tracking/documenting the same -for future use. - - - - -Responsible for merge with the trunk - - -The branch owner will be responsible for ensuring that the changes in -the branch can be successfully merged with the main trunk at a reasonable point -in time. - - - - - - - -§ion2-tagrelease; - -As part of the release process, the entire code base must be tagged with an -identifier that can help in uniquely identifying the release. A tag gives a -label to the collection of revisions represented by one developer's working -copy (usually, that working copy is completely up to date so the tag name is -attached to the latest and greatest revisions in the -repository). - -The identifier for the tag should provide enough information to -identify the release at any point in time in the future. One suggested tag -identifier is of the form. - - - release_{major version #}_{minor version #} - - - As one reader pointed out to me, a good practice here is to tag -the release first. Checkout the entire codebase using the tag, and then -proceed to go through a build / deploy / test process before making the -actual release. This will absolutely ensure that what leaves the -door is a verified and tested codebase. - - - - -§ion2-branchatrelease; - -After each software release, once the &CVSAB; repository is tagged, a -branch has to be immediately created. This branch will serve as the bug fix -baseline for that release. This branch is created only if the release is -not a bug fix or patch release in the first place. Patches that have to be -made for this release at any point in time in the future will be developed -on this branch. The main trunk will be used for ongoing product -development. - -With this arrangement, the changes in the code for the ongoing -development will be on the main trunk and the branch will provide a separate -partition for hot fixes and bug fix releases. - -The identifier for the branch name can be of the form. - - -release_{major version #}_{minor version #}_patches - - - - - -§ion2-bugfixbranches; - -This practice extends from the previous practice of creating a -separate branch after a major release. The branch will serve as the code -base for all bug fixes and patch release that have to be made. Thus, there -is a separate repository sandbox where the hot fixes and -patches can be developed apart from the mainstream development. - -This practice also ensures that bug fixes done to previous releases do -not mysteriously affect the mainstream version. In addition, new features -added to the mainstream version do not creep into the patch release -accidentally. - - - - -§ion2-patchesfrombranches; - -Since all the bug fixes for a given release are done on its -corresponding branch, the patch releases are made from the branch. This -ensures that there is no confusion on the feature set that is released as -part of the patch release. - -After the patch release is made, the branch has to be tagged using the - release tagging practice (see ). - - - - - - - - -§ion1-chgpropagation; -Change propagation practices explore how changes made to one version of -the application are migrated to other living versions of the application. - - - -§ion2-mergebugfix; - -After each release from a branch, the changes made to the branch -should be merged with the trunk. This ensures that all the bug fixes made -to the patch release are properly incorporated into future releases of the -application. - -This merge could potentially be time consuming depending on the amount -of changes made to the trunk and the branch being merged. In fact, it will -probably result in a lot of conflicts in &CVSAB; resulting in manual merges. -After the merge, the trunk code base must be tested to verify that the -application is in proper working order. This must be kept in mind while -preparing the project schedule. - -In the case of changes occurring on branches for a long period, -these changes can be merged to the main branch on a regular basis even -before the release is made. The frequency of merge is done based on certain -logical points in the branch's evolution. To ensure that duplicate merging -does not occur, the following practice can be adopted. - -In addition to the branch tag, a tag called {branch_name}_MERGED -should be created. This is initially at the same level as the last release -tag for the branch. This tag is then moved after each -intermediate merge by using the -F option. This -eliminates duplicate merging issues during intermediate merges. - - - - - - -§ion1-softwarebuild; - -This section deals with the best practices for software builds. Build -is the process of creating the application binaries for a software release. -They are done in a periodic manner by the build teams to provide baseline -binaries for daily work. - - -§ion2-bebo; (<acronym>BEBO</acronym>) - -A variation of this adage has been around in the &OPENSOURCE; -community called "Release Early and Release Often" for quite some time -albeit for a different reason. BEBO helps a development team identify -issues that can arise from checking in the wrong files. BEBO will address -integration issues at the application level that might have slipped passed -individual developer builds. It will also improve the team morale when they -see a working version of the application. - -Builds must be done on a regular basis. There should be a dedicated -resource(s) assigned to do the same. The entire project team must be -trained to view the daily build as an important activity and not as a chore. -Builds must be completed without any failures on a regular basis. Build -failures must be a rare event and should be treated with utmost seriousness. -The project team should ensure that successful builds are top priority on -their agenda. The seriousness can be emphasised by setting up a penalty for -breaking the build. - -Each build can be tagged in CVS using a standard naming convention. -This can help developers checkout a working version of the entire system -from daily builds for local development. - - - - -§ion2-automate; - -Another key practice for software builds is to automate the build -process completely. The automation process must also include automatic -retrieval of the right source files from the &CVSAB; repository. This -ensures that the build process is completely repeatable and consistent. In -addition, the chances of a build with the wrong version of the application -source files are reduced to a large degree. - -By automating the build process, the task of building often becomes -less burdensome. - - - - -§ion2-ensurecheckin; - -This adage sounds trivial at first but this problem is very common -even with experienced development teams due to oversight. The problem of -oversight cannot be easily addressed since the onus is on the individual -developer to ensure that his or her file has been checked in. This practice -should be drummed into the team in the form of training and pre-build -announcements to ensure that the right version of source code is available -in the repository. - -Automated build process as explained above will help in catching this -problem to a certain degree since they will automatically take the source -code from the &CVSAB; repository and perform the software build. Any missed -items will surface during the build process itself (makefiles etc.,) or -during the regression testing of the product (older version of the file -checked in). - -A penalty based system can be setup to handle wrong check-in. Having a -kitty for a post project party to which each person who makes a wrong check-in -will contribute a fixed amount will act a good penalty system. - - - - - - - -§ion1-instprocess; - -Here we will look at the best practices for institutionalizing &CVSAB; -usage in the organization. - - - -§ion2-chngmgmt; - -All organizations must implement a good Change management process -(CMP). A good CMP will define how changes are received, -recorded, tracked, executed and delivered. &CVSAB; provides version -control for your project. Change management addresses the bigger -picture of how enhancements and bugs are received, tracked and -closed. &CVSAB; will play a smaller but a very important part in this -entire picture. With a formal change management process in place in the -organization, tools such as &CVSAB; will be looked at as aiding this process -instead of acting as a general development overhead. - -Change management is quite a vast topic that cannot be done justice -here. Please look up other sources of information on change management. - - - - -§ion2-objectives; - -To institutionalize &CVSAB;, it can be made as part of the performance -objectives for the developer to use &CVSAB; in the project. In addition, it -can also be made as part of the objective for the project manager to deploy -&CVSAB; in his or her project. - -Compliance of this can then be reviewed as part of the appraisal cycle -for the employee. - - - - -§ion2-metrics; - -&CVSAB; usage metrics can be collected in terms of percentage of -deployment in the organization, project size handled etc., This information -will spur other line managers and program managers to look at &CVSAB; as a -tool that will aid them in their daily operations. - - - - - - -Best Practices in Action - -The best way to explain the need for these best practices is by -putting together an example of a real world project scenario and show how -exactly will these best practices fit into the bigger -picture. Also, a lot of readers have told me that the sections on - -and will require examples for better -explanation. Listening to the readers is a Good Thing so I have -put together a particular project scenario and then create a series of -events to show how the best practices, if followed, would help is making -operations smoother. - - -Inception - -Consider a software project where version 1.0 has just been put into -production and everyone is done celebrating. The next step is to start -working on the new features of the subsequent release. Also, the users of -the system have started to use it full-time and bug reports of various -levels have started to come in. - - Before jumping into new enhancements or bug fixes, the best practices - for should be followed. Few of - the important practices are and - . These practices will - effectively established two development environments, - one for regular enhancements and the other for bug fixes and minor - enhancements on the last release. - - -Let us assume that the release was tagged as - -release_1_0 - - -Then the branch was created with the branch name - -release_1_0_patches - - - - - -Development and Delivery - -Now, we are ready for business. Let us examine the bug fixes and -enhancements track. Assume that there are three bugs of which two are of a -high priority that should be fixed right away (possibly within a week) and the -third can be delivered after some time (say after 4 weeks). In the -middle of this schedule there is a regular release scheduled in three weeks. -Considering that we have a busy month ahead, let us see how exactly we can -use the Best practices to ease the days ahead. - -The timeline for the various release in the next month looks like this. - - - Fix Enhancement Fix - Today Release 1 Release Release 2 - |_______|______________|_________| - Time --> - - -We have two teams, one working on the bug fix branch and another team - working on the features for the next release on the main trunk. These - teams must make sure that they start out with the right version in - their sandbox. - - - - -The bug fix team will check out using the command line - - -cvs checkout -R -r release_1_0_patches {project name} - - - -The team that is working on the next release will use the command line - - -cvs checkout -R {project name} - - - - - - As soon as the bug fix team completes the two top priority bugs, they -will update, verify a successful build and commit their changes to the bug -fix branch using the command line - - -cvs update -R -r release_1_0_patches {module name} - - -The team should perform a build at this point to verify that the -update did not break any code on the branch. Once the build is successful, -the branch should be committed back into the repository. - - -cvs commit -R -r release_1_0_patches {module name} - - - : On a daily basis, each developer -will check in code to &CVSAB; and to ensure sanity of code, daily builds on -the bug fixed branch will be undertaken by checking out from -&CVSAB; on a clean environment and completely rebuilt. These daily builds -can be tagged in &CVSAB; using the following naming convention - -build_1_1_yyyymmdd : for the branch -build_2_0_yyyymmdd : for the trunk - - -The regular process of build-test-fix is followed to make a version -ready for delivery. The tag will help developers checkout a working copy of -the latest build as and when necessary. - - When the source code is released to the outside world, two practices -have to be followed. - - - - : This ensures that the bug fix -release is tagged correctly and so can be traced out at a later point in -time if necessary. - - - - : This ensures that the bug fix -is merged back into the main trunk ensuring that all future -releases is a truly cumulative delivery. - - - - - - - - - -Conclusion - -These best practices are meant to help software teams get a head start -on using &CVSAB; for their development. The ideas presented here have to be -constantly reviewed and evolved. I would like this to be a growing and -evolving document. Please send your comments and ideas to -&MYEMAIL; - - - - -&GFDL-FILE; - -
diff --git a/LDP/ref/docbook/CVS-BestPractices/cvs-bestpractices.xml b/LDP/ref/docbook/CVS-BestPractices/cvs-bestpractices.xml new file mode 120000 index 00000000..122f9e55 --- /dev/null +++ b/LDP/ref/docbook/CVS-BestPractices/cvs-bestpractices.xml @@ -0,0 +1 @@ +cvs-bestpractices.xml \ No newline at end of file diff --git a/LDP/users/Jason-Evans/Linux-Complete-Backup-and-Recovery-HOWTO-REWRITE/Linux-Complete-Backup-and-Recovery-HOWTO-REWRITE.adoc b/LDP/users/Jason-Evans/Linux-Complete-Backup-and-Recovery-HOWTO-REWRITE/Linux-Complete-Backup-and-Recovery-HOWTO-REWRITE.adoc index d40f4799..0dccc14f 100755 --- a/LDP/users/Jason-Evans/Linux-Complete-Backup-and-Recovery-HOWTO-REWRITE/Linux-Complete-Backup-and-Recovery-HOWTO-REWRITE.adoc +++ b/LDP/users/Jason-Evans/Linux-Complete-Backup-and-Recovery-HOWTO-REWRITE/Linux-Complete-Backup-and-Recovery-HOWTO-REWRITE.adoc @@ -44,6 +44,8 @@ Thanks to Larisa Alekseeva for your support and to the http://trilug.org[Triangl Thanks to http://www.charlescurley.com/[Charles Curley] for creating the original http://tldp.org/HOWTO/Linux-Complete-Backup-and-Recovery-HOWTO/index.html[Linux Complete Backup and Recovery HOWTO] +Thanks to Ubuntu for the https://help.ubuntu.com/lts/serverguide/backup-shellscripts.html[tar script]. + == Feedback Feedback is most certainly welcome for this document. Without your corrections, suggestions and other input, this document wouldn't exist. Please send your additions, comments and criticisms to me at: jason.s.evans@gmail.com @@ -65,9 +67,65 @@ Do your normal backups on their regular schedule. This HOWTO is useless if you d All examples in this HOWTO will be performed on fresh installations of https://www.digitalocean.com/community/tutorials/how-to-install-linux-apache-mysql-php-lamp-stack-on-centos-7[CentOS 7] and https://www.digitalocean.com/community/tutorials/how-to-install-linux-apache-mysql-php-lamp-stack-on-ubuntu-14-04[Ubuntu 14.04 LTS]. You can use the linked HOWTO's to bring your test system up to the same level if you wish. I will also create a small MySQL database using steps from https://codex.wordpress.org/Installing_WordPress#Using_the_MySQL_Client[Wordpress] in order to show how to backup and restore it. -== What do I need to back up? +== Where do we begin? + +=== What do I need to back up? There are three directories that absolutely must be backed up: `/home`, `/var/www`, and `/etc` as well as the MySQL database. -=== Where do we begin? + + +The following shell script uses tar to create an archive file on a remotely mounted NFS file system. The archive filename is determined using additional command line utilities. + +[source,bash] +---- +#!/bin/bash +#################################### +# +# Backup to NFS mount script. +# +#################################### + +# What to backup. +backup_files="/home /var/spool/mail /etc /root /boot /opt" + +# Where to backup to. +dest="/mnt/backup" + +# Create archive filename. +day=$(date +%A) +hostname=$(hostname -s) +archive_file="$hostname-$day.tgz" + +# Print start status message. +echo "Backing up $backup_files to $dest/$archive_file" +date +echo + +# Backup the files using tar. +tar czf $dest/$archive_file $backup_files + +# Print end status message. +echo +echo "Backup finished" +date + +# Long listing of files in $dest to check file sizes. +ls -lh $dest +---- + +.$backup_files: a variable listing which directories you would like to backup. The list should be customised to fit your needs. +.$day: a variable holding the day of the week (Monday, Tuesday, Wednesday, etc). This is used to create an archive file for each day of the week, giving a backup history of seven days. There are other ways to accomplish this including using the date utility. +.$hostname: variable containing the short hostname of the system. Using the hostname in the archive filename gives you the option of placing daily archive files from multiple systems in the same directory. +.$archive_file: the full archive filename. +.$dest: destination of the archive file. The directory needs to be created and in this case mounted before executing the backup script. See Network File System (NFS) for details of using NFS. +.status messages: optional messages printed to the console using the echo utility. +.ar czf $dest/$archive_file $backup_files: the tar command used to create the archive file. +..c: creates an archive. +..z: filter the archive through the gzip utility compressing the archive. +..f: output to an archive file. Otherwise the tar output will be sent to STDOUT. +.ls -lh $dest: optional statement prints a -l long listing in -h human readable format of the destination directory. This is useful for a quick file size check of the archive file. This check should not replace testing the archive file. + +This is a simple example of a backup shell script; however there are many options that can be included in such a script. See References for links to resources providing more in-depth shell scripting information. +