# A Backup Strategy

What follows is one recommended backup strategy. As of Synk 5, Synk is capable of backing up an entire disk when running as root, but the suggestions below still remain in effect--a fresh install is still the best way to restore an operating system.

## What files should I back up?

Rule #1: Stay home.

OS X is a UNIX-based operating system that relies on the specific structure of its files. Many files are in hidden directories and can only be accessed from the command line in the Terminal application.

The safest way to work in Mac OS X is to store all of your data files in your home directory. The old "Macintosh way," with folders and files and aliases all over the hard drive is no longer practical.

Once you have moved your files into your home directory, backup is a simple matter of defining the source folder as your home directory. Create a backup folder on an external drive and call it "Home Backup." Define this folder as your destination folder.

While you are creating folders, make an "Archive Folder" that will store all the versions of your modified files. Define this folder as your archive folder in the Archive tab.

## But what about system files?

Rule #2: If you do not know what a file is, you do not know how to restore it properly.

There are tens of thousands of files spread across many folders in OS X. The safest and most practical way to restore these files is from the original System Install CD.

After you have re-installed your system, you will need to apply the various updates. The best way to do this, if you have a broadband internet connection, is to just let the Software Update application download and apply the appropriate updates. While it is possible to keep copies of all of the updaters (see below), Software Update will know which updates are already merged into later updates. For example, you may have originially updated piecewise from 10.3.0 to 10.3.1 to 10.3.2 and so forth, but Software Update can download a single update that will take you all the way to the most recent version. This update will usually also includes all security updates and so forth along the way, saving you time and energy reinstalling them.

If you have a slow internet connection, you can keep updates in a folder called "Updaters" that is located in your home directory. When installing a new update, rather than clicking the "install" button in the window, you should choose "Install and Keep Package" from the File menu. Save it in your "Updaters" folder and you will not have to download it again to re-install. These updaters will be backed up with the other files in your home directory.

Another option is to keep a CD-RW of your updaters. Make a new one when new updaters become available.

## How do I back up applications?

Rule #3: Fresh is best.

How to restore applications depends on the specifics of each application. Some need to be re-installed from the original disks. Others contain all they need within the application itself. Synk, for instance, can be dragged from one volume to another and needs no special installation. (Its preference file is located in your ~/Library/Preferences folder, and the scheduler keeps the schedule in /Library/Application Support/Synk Scheduler, but you can always simply reset these choices on the new system.)

You are safest re-installing the applications from their original install media, but keep the following in mind:

- Application support files that are common to all users of your computer are stored in the Library folder at the root level of your startup disk. Backing up this directory should not be necessary but you should verify that your application is not storing important data in this folder.
- Some programs store data within the Applications folder. If at all possible, change the offending application's preference settings to relocate data files into a folder within your home directory.

## Partitioning your disk (optional, for advanced users only)

Rule #4: Divide and conquer.

If your data can be separated from the system, then the backup and restore process becomes much simpler. This is because the entire system can be replaced without touching your home directory. The way to separate your data from your system is to partition the drive into more than one volume.

Mac OS X expects the startup disk volume to hold all of its working files and all of the applications. There must also be room for the virtual memory swap file, which can grow quite large. It is very difficult to work around these expectations, so it is best to accept the default location for the applications.

To create more than one partition, startup from your Mac OS X System CD-ROM and use the Drive Setup program found in the menu of the Mac OS X installer. This process will erase all the data on your drive! So plan ahead and make sure that all your important documents are burned onto a CD-R or copied to another drive.

You must make sure that the startup partition is large enough to contain the system plus all the applications you will be installing. A very minimum install would be 2 gigabytes, but at least 4 gigabytes is recommended. A good partition strategy for a drive would be two partitions:

- 8 gigabytes for OS X
- the rest for your personal data
- (optionally, a third "backup" partition)

After partitioning your drive, insert the OS X startup disk and run the installer. Choose the 8 gigabyte partition for installing OS X.

By default, the system installer places your home directory on the startup partition (which, in this case, is the 8 gigabyte partition). This can be changed with a program called NetInfo Manager that is located in your Applications/Utilities folder. Relocating your home directory to another partition will save space on your startup disk as well as making it much easier to restore a malfunctioning system. If your home directory is not on your startup partition you can format and restore the system without erasing your home directory.

## To change the location of your home directory:

1. Copy your entire home directory to another partition
2. Open the NetInfo Manager application
3. Authenticate NetInfo as an administrator (the Domain>Security>Authenticate menu choice)
4. Locate and select the /users/my_login_name item in the NetInfo directory browser
5. Change the "home" property to the path of the directory you wish to use... an example on a second partition would be "/Volumes/Partition2/my_login"
6. Quit the NetInfo program and update the changes

After re-installing a system, you will need to change your home directory in NetInfo again because the installer will create a default directory for your home on the startup disk.

Also note that keeping your backup on a separate partition on the same disk does not protect you from a failure of that disk. The safest backups are to an entity outside of your computer system, and ideally outside of your home, city, and even state/country as well. Backing up regularly doesn't give you any benefit if the backups are destroyed along with the originals.

## Backing Up

If you have followed the above advice, you have separated your data from the system.

To use Synk as a backup program, you either need a third partition or a second drive available that is large enough to contain all the data in your home partition.

- The backup volume must be mounted on the desktop.
- The initial backup may be accomplished with a Finder copy, as Synk's incremental copy is overkill for this situation. Drag your entire home directory onto the backup volume. This will create a new folder and backup all your files. Rename this backup folder to eliminate confusion.
- Create another folder on this volume called "Archive."
- Create a new Synk document and define your source folder to be your home directory.
- Your destination folder will be the "backup" home folder you copied to the backup volume.
- Set the action to Backup so that the arrow is pointing from your home folder to the "backup" home folder.
- Check the archive option and locate the "Archive" folder on the backup volume.

When you run this document, Synk will compare the file modification dates and the modified ones will be copied to your backup.

## Restoring

If you have accidentally deleted or damaged a file, you can find the most recently backed up file in your "backup" home folder. Earlier versions will have been archived in the "archive" folder.

To restore a damaged system, simply restart from your Mac OS X install CD and initialize and re-install your system and applications. If you followed the advice to save your updates into an "Updaters" folder in your home directory, then you can easily reapply the updates in the order that they were downloaded. Simply double click on a ".pkg" file and the installer will open and allow you to apply the update. Or, simply allow the Software Update control panel to download and install them for you.

After doing this, you must change the home directory in NetInfo and all your settings will be restored because they are stored in your home directory Library folder.