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DATA STORAGE REQUIREMENTS
There is a data explosion taking place. Industry analysts agree that company data stored on laptops, desktops, and servers doubles annually.
This rapid expansion of both necessary and unnecessary data can strain company resources as they grow. Consider how a simple, manageable Excel spreadsheet can migrate and multiply into several additional, more complex documents with embedded images, links, and charts.
Every company, no matter how small, needs to back up its data. It's that simple.
SMBs today are faced with the fragile balance of operating costs increasing while business continues to grow. As companies grow, data management requirements also grow exponentially and the IT staff feels the strain. Each new server increases backup requirements; backup windows shrink; and determining what to back up and how often quadruples in complexity and cost.
Once a business clears the financial hurdle and begins to plan their data protection strategy the choices can appear daunting. Do they select tape or disk? Apply differential or incremental backups? How much will a new system cost and how much time will it take to implement? What data should be included in the backup? This article attempts to address these concerns.
TRADITIONAL BACKUP STRATEGIES
Deciding what data to back up should be the first step. Businesses should identify files that change frequently, and any programs and files that keep the business up and running.
Once systems and files are identified the next step is to perform a full backup of all these systems, applications and data files. A duplicate archive should be created and kept off-site for disaster recovery purposes.
If many system files contain unique user settings and passwords that change often, a daily backup schedule may be needed. Unfortunately, the cost and time required to complete full backups each day is impractical, especially for a company with large amounts of data or limited backup windows.
Alternative backup methods, such as differential or incremental backups, conserve time and resources and minimize strain on the network. This is where the simplicity typically ends. Incremental and differential backup strategies reduce a company's backup window by eliminating daily full backups, but have disadvantages that may offset the gains.
Differential Backups
Differential backups record all new, updated or deleted files since the last full backup, capturing files at points in time. Let's look at a typical scenario.
During any given week a company could run a full backup between Friday and Sunday. Differential backups are then run for files that have changed between Sunday and Monday; Sunday and Tuesday; Sunday and Wednesday; and finally, Sunday and Thursday. Thursday's backup would then include all changes since Sunday.
Differential backups offer faster restore times and greater flexibility for the user; however, this type of backup will result in redundant data sets. Since any changes on Tuesday are also captured on the Thursday backup, this approach uses up more storage capacity and takes longer and longer to complete.
Incremental Backups
Incremental backups remember which files were captured on the previous backup, regardless of whether that backup was full or partial. Using the same scenario, a full backup is again performed over the weekend. Incremental backups are then run for files that have changed between Sunday and Monday; Monday and Tuesday; Tuesday and Wednesday; and Wednesday and Thursday. Subsequent incremental backups only capture files that have changed since the last incremental process, so the data load is smaller and the backup time is reduced.
Unfortunately, it takes longer to restore data from an incremental backup. Data from the most recent full backup must be located and restored, and then data from all the incremental backups must be restored in the proper sequence. For example, if you want to restore a file from Wednesday, you would need to reload the full backup from the weekend and then restore each sequential backup set from Monday, Tuesday, Wednesday and Thursday. Not only is this process time-consuming, it also results in flawed restores that recover files that were previously moved, changed, or deleted.
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