The purpose of this article is not to convince you to use file synchronization software instead of backup software, but rather to supplement your backup procedures using synchronization jobs. File synchronization is not a replacement for a full image backup of your system drive (unless you’re talking RAID).
Computer data backups are essentially the same as file synchronization. Both make a copy of your data in a different physical location, so that it can be restored later if needed. Granted, this is a much generalized, simplistic statement. What follows are a few differences.
How Backup Software Works
Backup software typically scans the data files on hard disk A, and copies them to a backup container file on hard drive B. The container file can be called a backup image, backup file, backup archive or it can be split into multiple container files so that they can be copied to a DVD.
Bottom line is that they are contained in some form on the destination location. Typically, they are also compressed so that the resulting file size is smaller.
If you need to recover a file from the backup, then you need the backup software to provide you with a user interface to browse the backup and restore just the selected files, or all of them if needed.
The backup process gets more complicated if you only want to backup changes instead of all the files on a particle hard drive or in a specific folder. If you want to backup only the changes since the previous backup it is called an “Incremental Backup”. If you want to backup only the changes since the last full backup it is called a “Differential Backup”.
The reason for different options to backing up either “Incrementally” or “Differentially” is how they are restored.
For Incremental backups the restored procedure starts with the first full archive, then processes each incremental one after it to net out the changes to a particular file or files you are restoring. For example, you do a full backup on Sunday, then incremental backups on each day after until the next Sunday. On Friday though, you find the need to restore a file. You use your backup software to locate it. If you’re lucky, the backup software will hide all of these complexities from you and you can simply select which day you want to restore from.
A Differential backup differs in that all of the changes since the last full backup are saved each time. So with the Monday thru Saturday daily backups, all of the changes since the full Sunday backup will be backed up each day. On Friday, the restore simply needs to scan thru the Sunday, plus the last differential backup on Friday to get your current file version. No need to process each day in between.
You can skip the whole “Incremental” and “Differential” routine, but then a full backup every day will use the greatest amount of disk space on the destination hard drive.
How File Synchronization Software Works
File synchronization software simply takes your view of a folder on your computer with all of its files and subfolders and makes another copy of it. It can copy to another location on your existing hard drive, a different hard drive connected to your computer, a hard drive connected to a different computer, a network storage device or even cloud storage.
The benefit of synchronization is that you have this exact copy of data in a form you can use and work on the same as where it originated from. There are no destination containers which you need special software to be able to explore with.
One limiting factor is that you can’t change the same document in both locations at the same time. When the sync software next runs, this will trigger an error as it will not know which copy to keep. Some synchronization software products will have an option to append a timestamp to the files involved in these kinds of conflicts so that at the very least all versions of the file exist on both sides.
Typically deletions are propagated also. If you delete a file from your computer, then the synchronization process will replicate and delete the same file on the destination location. Options are usually enabled by default in these cases to save a copy of the deleted file in a safe folder location for a certain number of days.
Synchronization jobs can typically be scheduled to run periodically much the same as backup software. The difference when syncing is that every job run is incremental, with the end result the same copy of data.
Despite the transparency of data which synchronizing achieves, it’s not a replacement for backup. Unless the only data you care about is your own user data. If the amount of your user data is not large, and you have the original distribution media for all of your operating system and user applications then you could probably get by with just synchronizing your data to another location.
Tasks for a Rewarding Synchronization Job
- Don’t synchronize your entire system hard drive. Backup software is better suited to this task. If you truly want your hard drive synchronized at all times, then investigate your RAID technology options.
- Organize your data. I’ve already written about using Windows 7 Libraries for this task.
- If you have a lot of user data to synchronize, break it up into more manageable chunks of data to work with. For example, configure one sync job to handle your “My Documents” data, another with your “My Pictures” data and another for your “My Videos”.
- Synchronization software allows you to configure jobs which can automatically run at certain times of the days and also periodic jobs which run at certain intervals e.g. every 2 hours.
Be careful when mixing these two types of jobs against the same source of data. For example, every two hours you want to synchronize your documents data to your external hard drive. Then at night, you want a daily job to synchronize the same data to your laptop computer.
This is fine as long as the two jobs do not run at the same time, which you can control using time of day scheduling. But with periodic scheduling involved, at some point both jobs will run at the same time. In our example if you depend on the daily job to always complete, it may not do so some days as the software will typically cancel one of the jobs if the source data is no longer considered accurate.
- You are on your own with data compression. If you have folders being synchronized which contain hundreds or thousands of files, consider compressing this folder into a single archive file using software like WinZip.
Not only will this reduce the amount of disk storage space required, but for cloud storage service the quantity of files can affect both the performance of the synchronization job and the cost from your cloud storage provider.
Typically they charge a small amount for GETS, PUTS and LIST types of operations. Even if it’s a penny per 1000 of these, it can quickly add up if you have thousands of files to be processed every day.
- The first time you run a synchronization job is always going to take the longest. This is because all of the data needs to be copied the first time. Subsequent jobs will be much quicker, assuming of course you don’t change everything. Therefore it may be best to manually run the first time before scheduling an automatic job.
- Synchronization software allows you to focus on just your most important data. It gives you multiple copies of this data and makes it more manageable and affordable to copy it to cloud storage providers.
One, two and three terabyte hard drives are getting less and less expensive every day. But it’s still not easy to upload that much data in a timely and affordable way to an online service. Know which of your data is most important and keep it synchronized.
- If keeping prior versions of data is a requirement for you, then using synchronization methods might not be your best option, unless your synchronization software gives you the option of saving replaced files. For example, you have a Word document which is finished one day, but then the next day you do mass edits and rewrites to it, only then to realize the third day you wanted to keep the first copy… Your other option is to make copies of data before doing mass edits and rewrites like this.
Remember, good synchronization software is not a replacement for good backup software. It is a supplement, giving you multiple copies of your most important data that are easily accessible.