Volume Number: 20 (2004)
Issue Number: 12
Column Tag: Programming

Backup! Backup! Backup!

by Brad Belyeu

Data Security for the Extremely Paranoid

Welcome

It's similar to earthquake, fire, or (where I'm from) tornado drills. You hope you never have to use it, but you do it in case of emergencies. Such is the case with data backups. A major problem with backing up data is that it changes so frequently. A backup is only as good as it is current. Applying Murphy's Law to a backup situation means that disaster is going to strike when you haven't ran a backup for some time. When is that last time you've backed up your data?

Why Should I Backup?

Hopefully you've never had to deal with data loss, but if you have I'm sure that you understand the necessity of backing up your data. In my experience, most businesses are so dependent on computer data that they would go out of business if they lost it all overnight. Imagine working on a programming project for work or school over the last several months and then losing it all and starting over. To make modern an old adage, "A Megabyte in time, saves nine."

Here are the most common reasons you should keep a current backup:

• The most overlooked reason why you should frequently backup, is accidental deletion or corruption. What if you're working hard on a file and your Mac shuts off, and you reboot only to find that the file you were working with will no longer open because it is corrupted. You or someone else using your machine could accidentally delete the file or make changes to it that you want to undo. There are numerous scenarios that could effect the security of your data.
  
  
• Hard drives crash! This is something we all have to live with. Hard drives are basically read/write heads hovering a fraction of an inch over the top of platters that are spinning 7,200 times/minute all inside an airtight seal. A small speck of dust would be detrimental! Having professionally serviced Macintosh computers for years, I know that hard drives are one of the most common components to fail.
  
  
• If you're a notebook user, your Mac is a prime target for theft. Mac iBooks and PowerBooks have a high resell value. If you like to carry yours around, you should make sure you have critical files backed up in a safe place.
  
  
• Natural disaster/fire seems rather unlikely, but it does happen. Insurance might pay for you to get a new computer, but they can't recreate your data for you if you didn't backup. In this case, not only do you need to backup, but also you need to backup your data to a different physical location.
  
  
• Viruses aren't currently a problem for OS X users but could be in the future. Viruses have been known to delete files or corrupt entire drives. This shouldn't be overlooked as a good reason to have a recent backup.

Media & Software

With current technologies, there are a variety of ways to backup your data. Not all backup options are created equal though. I'll rate each option on capacity, dependability, speed, & price.

• Zip disks are slowly fading into antiquity. I say slowly because there are a lot of die-hard zip users out there, and in its day a zip disk was one of the best backup options you had. Today there are options that offer more space for less money. Internal zip drives aren't sold in many retail stores, but a 750mb zip drive can be purchased from Iomega online for $149.99. The disks are around $15 each when purchased individually. Assuming you already have the drive that's around two cents per megabyte. The 250mb zip drives are much more common and can be purchased for $100 online. The disks can be found for lessthan $15 per disk. The rate at which data can be stored to or retrieved from the disk is average. Zip disks can be overwritten and reused, but they are not permanent. Zip disks will go bad eventually, just ask anyone who's used them much. Zips can be stored off-site, but as with any magnetic disk, you don't want to store your disk next to any kind of a magnetic device. Overall, zip disk backups are better than no backups at all; but there are better options.
  
  
• CD burner drives are a better option than zip drives in my opinion. Creating CD backups is definitely the cheapest option available for users with moderate backup needs, and any new computer purchased will come with a recordable CD drive. 700mb CD-R discs can be purchased for a fraction of a dollar each. When a CD-R is full, you can't write over any of the files. If you use an application like Toast, multiple sessions can be written to a CD-R until the disc is full though. Normally when backing up to CDs, you'll just through away your older backups. CD-RW discs are more expensive but allow you to erase and rewrite the disc. The problem with CD-RWs is that the process of erasing and reusing them is time consuming, and there are a limited number of times a disc can be erased and reused. The speed of writing to a CD with current technology is pretty fast and retrieving data from a CD is quicker than most data backup options. CDs are a dependable backup as long as you have a good case to store them in. If you're just throwing them in your desk drawer, they scratch easily making the data on them hard to retrieve. CDs are a good option for people needing a modest backup option for specific files or folders. But someone who wants to backup an entire drive or large folders will face the inconveniences of using multiple CDs to store the data. There are better options for those looking for large-scale backups.
  
  
• DVD burner drives offer many of the same benefits as a CD backup, but they will hold over six times the amount of data that a CD will hold. A single layer DVD will store over 4GB while a dual layer will store 8GB! As of this writing, dual layer drives are available for purchase, but I haven't been able to find dual layer disks anywhere. The cost on backing up to DVD is more per disk; but considering that you can fit so much more data on a disc, it evens out to about the same per megabyte. With the costs of DVD discs falling and the speed of DVD drives improving, DVD backups are the way of the future.
  
  
• USB Thumb drives (a.k.a. flash drives, jump drives) have become a recent addition to the backup arsenal. While most people use these devices for transporting data, they can also be used for data backup. These drives are very diverse in both size and price. A 512mb drive can be purchased online for around $50. Considering you don't have to purchase disks and data can be rewritten indefinitely, thumb drives are bargain option for small-scale backups. Also because there are no moving parts the drives have a very long lifespan. The only problem with them is that because they are so small they can be easily lost or stolen. With most of the new thumb drives coming with USB 2.0 speeds, they offer a decent speed at which files can be stored and retrieved. I have a thumb drive that I use specifically to backup my QuickBooks data file. This is, of course, in addition to my other methods of backup. Every fourth time you exit QuickBooks it will ask you if you'd like to back up your data. At that point I plug in my thumb drive, click 'Yes', and navigate the menus to the mounted drive. After saving the file, I dismount the drive and put it away until next time. Thumb drives make for stylish, easy, and cheap backups. There are only two drawbacks to using thumb drives that I can see. First, the drives aren't (yet) large enough for me to backup my entire system. Secondly, it would be an easy item for someone to steal which puts my important data at high-risk.
  
  
• The best option for backing up large amounts of data is to another hard disk. If you need a large-scale backup, a secondary drive is the most affordable and time effective way to backup your data. There are several ways to do this. The drive could be setup with a similar drive to create a RAID (redundant array of indexed disks). I strongly suggest that people create a mirrored RAID instead of a striped RAID because your data is much safer. In a mirrored RAID, data is mirrored on each drive. The drives end up being an exact copy of one another. Inside your operating system they appear to function as one drive. But if one of your drives ever fails, your data is completely safe on the second drive (assuming that both your drives didn't fail simultaneously, which is highly unlikely). The trick to setting this RAID up is that the drives must be setup before you can save data or install an OS on them. If you create a RAID with a disk that already has data on it, you will lose all the data on the drive because the drive must be repartitioned. To create a RAID disk with Disk Utility you must boot to another volume, and then start up Disk Utility (normally found in the Applications/Utilities folder). With one of the disks (not partitions) selected in the left panel, you can click on the RAID tab in the right panel. From there you drag the disks you want to use to create the RAID into the appropriate fields. After the RAID is setup, the two separate disks will appear as one in both Disk Utility and in the Finder. If one of your hard disks ever fails, you'll get a message with a chance to rebuild the RAID from the remaining disk. This saves your data in the case of a hard drive failure. Some people have a second internal drive that they backup to that is not setup as a RAID. Even though I recommend RAID, there are times when running the second drive independent from the first will work. More often an external hard drive is used to backup data from the primary drive. External hard drives are somewhat delicate pieces of equipment and shouldn't be transported more than necessary. If the drive falls several feet or gets slammed around at all, its likely to fail. But if handled with care, external drives can be a very dependable backup option.
  
  
• Another excellent way to backup your data is to a remote computer. Backing up to a remote computer presents its own set of challenges, such as bandwidth and security, but generally allows data to be stored in a secure environment away from your physical location. You can also backup to another server/computer on your LAN. If you're working in an environment with many users on multiple computers, setting up a central server for data backups is a very smart solution saving both time and money. When left up to end users, people usually neglect to backup their data. But with a server, the process can be automated with a variety of software packages and protocols, and a centralized administrator can make sure everyone is backing up on a regular basis.

Software Solutions

Of course you could just use the finder to drag and drop necessary items on a daily basis to your backup volume. But how boring is that. As programmers we believe that anything capable of being automated should be! Plus backups are far more likely to happen if we don't leave it up to people to remember daily.

• One very simple and affordable option for reliable and secure backups is a .Mac account. iBackup is a software package developed by Apple specifically for .Mac users. It can be used to backup to your iDisk which Apple recently expanded to 250mb. Apple's iDisk isn't large for a comprehensive backup, but some major items from your home folder can be backed up. I use some of the default suggestions and then added my mailboxes to the backup list. My contacts, stickies, calendars, passwords, mailboxes, some business documents all fit easily inside my allotted space. iBackup can also be used to backup to a CD, DVD, or another hard drive making it a flexible utility. Because it allows the capability to backup to another hard drive, you can actually backup to any volume mounted on your computer including network mounts. iBackup allows for you to schedule a time to perform regular backups; and as long as your computer is turned on, it will automate the entire process for you. iBackup is an excellent utility with one minor drawback- you must have a .Mac account for the software to work. The software checks in system preferences when you start it up for a valid username and password to .Mac. I believe my .Mac account is well worth the $99/year that I pay for it simply for the backup utility alone!
  
  
• There are many free options for backup software; but if you're in a business environment, you'll probably want the power and flexibility of a commercial product. The great news is there are many great off-site backup packages that work with Mac OS X. These companies normally provide you with software and server space to backup. If you have large backups, this can get rather expensive, so in a small business environment, you might consider doing an off-site backup for your most critical data along with entire system backups daily in-house. One great application that can be used for remote or local backup is Retrospect. I've only used Retrospect Express, but it is a very powerful way to backup a lot of data to any type of media as routinely and quickly as possible.
  
  
• For those of us who don't want to pay a lot for backup software but still need our entire system backed up, Mike Bombich's Carbon Copy Cloner saves the day. CCC allows you to create a bootable backup of your volume by copying it to another hard disk. You can also choose to create an image file on the target disk instead of making a clone. CCC uses the ditto command to copy the entire drive including important resource forks. CCC also allows you to synchronize the source to the target only backing up items that have changed. This can save a great deal of time and processing power. Another option in the preferences allows to you encrypt the disk image saving it from prying eyes. CCC is a great shareware application that can be downloaded from: http://www.bombich.com/software.
  
  
• FTP can be another great way to backup. I've setup a SFTP server on my PowerMac to use as a backup server for my other computers. I recommend only using Secure FTP (SFTP) when backing up over a public network because it will encrypt your data. Most importantly it encrypts your username/password so that someone using a network sniffer can't steal that valuable information and gain access to your FTP server. My FTP client of choice is Transmit because of its great interface and apple scripting ability. I use it to automatically synchronize my iBook's home folder with a home folder on my PowerMac.

Transmit can be automated with some simple applescript. Open Script Editor (found in Applications/AppleScript/Script Editor) and try typing in the following script entering the appropriate values for your configuration to backup your home folder to a remote server running SFTP.

-- *** CONFIGURATION ***
set myServer to "169.127.0.1" -- Put your server address here
set myUsername to "MacTechReader" -- Put your username here
set myPassword to "password" -- Put your password here
set myServerPath to "/BackupHere" -- This is the path to save

-- on your server
set  myLocalPath to "/Users/MacTechReader" -- this is the path to backup
-- *** END CONFIGURATION ***

try
   tell application "Transmit"
      make new document at before front document
      -- Creates new window for use
		
       tell document 1
         if (connect to myServer as user myUsername with password
         myPassword with initial path myServerPath with
         connection type SFTP) then

         -- Tries to connect to the server with my username and password & the path
         -- specified using Secure FTP.
		
         if (set your stuff to myLocalPath) then
            synchronize direction upload 
            files method mirror with time offset 0
		 
         -- Uses the synchronize method to upload files and deletes files on the 
         -- server that are not found on the local computer.
		
               else
                  display dialog "Sorry. Could not set local folder."
            end if
 
         else
            display dialog "Sorry. Could not connect to remote server."
         end if
      end tell
   end tell
end try

delay 1

tell application "Transmit"
	activate
end tell

tell application "System Events"
 
   tell process "Transmit"
      tell window myServer
         keystroke return
      end tell
   end tell

end tell

tell application "Transmit"
   quit
end tell

Save this script and then you can insert it in your startup items (inside Accounts pane of System Preferences in OS 10.3). Transmit will automatically open and synchronize your files with the remote server on startup. If you don't reboot your Mac often, a crontab can be created to run the backup at a specific time of day at certain intervals using the osascript command. Cronnix is a shareware application that gives you a GUI to work with crontabs. CronniX and its documentation can be downloaded at http://www.koch-schmidt.de/cronnix.

This crontab is set to run at 8AM the first day of every week regardless of the day of the month or which month it is. The command osascript launches an applescript file from the command line and should be followed by the path and name of your applescript.

• Another good option for a quick backup is creating your own shell script. Ditto is a powerful command for backing up to a mounted volume, but rsync is an even better option. Rsync can be used to create a backup of a file on the same disk, another volume, or a remote host. According to its man-page there are eight different ways to use rsync, and they are:

There are eight different ways of using rsync. They are:

• For copying local files. This is invoked when neither source nor destination path contains a : separator.
  
  
• For copying from the local machine to a remote machine using a remote shell program as the transport (such as rsh or ssh). This is invoked when the destination path contains a single : separator.
  
  
• For copying from a remote machine to the local machine using a remote shell program. This is invoked when the source contains a : separator.
  
  
• For copying from a remote rsync server to the local machine. This is invoked when the source path contains a :: separator or a rsync:// URL.
  
  
• For copying from the local machine to a remote rsync server. This is invoked when the destination path contains a :: separator or a rsync:// URL.
  
  
• For copying from a remote machine using a remote shell program as the transport, using rsync server on the remote machine. This is invoked when the source path contains a :: separator and the --rsh=COMMAND (aka _-e COMMAND") option is also provided.
  
  
• For copying from the local machine to a remote machine using a remote shell program as the transport, using rsync server on the remote machine. This is invoked when the destination path contains a :: separator and the --rsh=COMMMAND option is also provided.
  
  
• For listing files on a remote machine. This is done the same way as rsync transfers except that you leave off the local destination.

Rsync is installed by default on Mac OS X, but if you need documentation or a download for another machine you can visit http://rsync.samba.org/features.html.

Rsync can be set to work without authentication if you are running a rsync server on the remote host. If you're not running rsync server remotely a password has to be entered to authenticate thus making an automated backup a little more difficult. Here's an example of a command you could put in a crontab specified to run at a particular time (keep in mind someone must type in the password before this will execute):

rsync -r /Users/myUsername/Documents
 
myUserName@myRemoteHost:/myRemoteDirectory

The -r option uses recursion to copy an entire directory. If you'd like more information on setting up a rsync server so that a username and password do not have to be entered, read the man page for rsyncd.conf for details.

Security & Encryption

If data is important enough to backup, you don't normally want just anyone to be able to read it. Precautions must be taken to make sure the data is safe from prying eyes. In a remote transfer, always be aware if the data is being sent encrypted. You can use ssh as an argument to rysnc and if a computer has remote login enabled you can encrypt your entire session. Secure FTP is encrypted during transmission, but not regular FTP. But even if you're backing up to an external hard disk, you might want to encrypt your data after it is stored in case of theft. If you use Carbon Copy Cloner you can tell it to create an image and encrypt it, otherwise you may want to use Disk Utility after the backup to create an image from your backup and encrypt it. After all the recently made-up Chinese proverb says, "Sometimes it is worse for data to fall into wrong hands than to be lost completely."

Brad Belyeu is the President of ABConsulting based out of Oklahoma City, OK. He is an Apple Certified Technician and a member of the Apple Consultant Network.