Time Machine

Time Machine

Designed to work with internal or external hard drives, the user can automatically retrieve data from disk images saved by time machine.  Time Machine saves backups in a "continious" setup which allows the user to access their harddrive today, yesterday, last week, and as far back as there is space to archive simutaneously.

Accessing these "fluid" daily save points does not require applying the image to the harddrive---data from previous saves can be copied out and pasted into the current harddrive to increase ease of document retrieval.  When using Time Machine you have access to Spotlight and Quicklook, which allow for quick comparison and retrieval of archived data.

Using Time Machine

The interface for Time Machine is rather straight-forward, you can have it backup entire drives for system-wide protection, or individual folders and files if space is an issue.  It requires you backup to a separate drive (partitions don't work) the drive must be HFS Macintosh Extended formatted and must be soley devoted to Time Machine.

A key note when protecting individual folders, Time Machine uses an exclusion process which means folders listed will --not- be backed up.  Take care to ensure you have excluded the correct directories, and not directories you want protected.  Once you have configured Time Machine it automatically takes images of the Harddrive hourly and then compiles them indo a day-long image at the end of the day.  If you would like to force a backup, simply select the icon on the menu-bar and choose "backup now."

If you happen to sleep/shutdown the computer in the middle of a Time Machine backup, it will automatically pause and resume as soon as the computer is back online.  If backing up to external drives, it will resume once the drive is re-connected.

Important Considerations

Since Time Machine creates continuous data restoration, if the user uses particularly large files (for example, database files, raw camera footage, etc.) then each alteration to said files will be stored in every daily image.  This will eat through harddrive space rather quickly on the backup volume.  Time Machine will does warn the user whenever an over-write of an old save-point is about to occur, but it may be easier to exclude particularly large files and have them backed up by shared drives on the network.

Shortcomings of Time Machine

There are only two chief concerns with Time Machine that bear notice.  The first of which is available drive space.  Time Machine really shines when given enough drive space to generate a long archived history of the life of the data drive.  Without a sufficiently large enough backup space, Time Machine is unable to give the user true mobility through their data history.

The second concern is that Time Machine is not an instantaneous fail-safe for data.  Raid Arrays would still take precedence in data protection as they provide instant backup for data.  Leopard takes hourly snapshots of the harddrive while Time Machine is running and then compiles them into a day-long image at the end of each day.  For this reason it is important that users understand how to force a backup (CTRL Click time machine Icon) when working with sensitive data.   

Comprehensive guide on using and troubleshooting Time Machine

Here is very helpful guide on Time Machine.