This article addresses some common questions about data backup.

Who Should Read This Guide?

Read this guide if you are responsible for protecting data in a small or medium business. It provides information about how to use backup and recovery and how to implement common backup strategies.

NOTE: Whether you already have a backup system in place or you are deciding to purchase our THETA RBackup solutions, you can find helpful advice in this guide.

Suppose for a moment that a virus infects your entire computer network. The virus spreads through every employee’s workstation, into every document and database file. All your work, all your data is destroyed. How would your business recover?

Without an adequate backup and recovery plan, your business is at risk. Because your company relies on its data and mission-critical applications, the cost of downtime is exorbitant, potentially exceeding thousands of dollars per hour for such expenses as recovering data and system files, replacing equipment, losing productivity, and losing customers. According to a recent disaster recovery study, nearly half of the companies that are unable to fully restore their data after a disaster will go out of business entirely.

Why Remote Backup Is The Ideal Backup Solution?

Whether you are backing up an individual workstation or a small network, remote backup is an ideal solution because it is capable of storing high capacities of information for a relatively low cost.

What Does It Mean To Back Up, Restore, And Archive?

Data backup is the process of transferring data from your company’s primary computer system to a separate storage device, such as a tape drive or off-site backup server. If the original data is lost or damaged, you can restore the information from the device/remote server and resume normal business operations. An archive is a long-term, permanent data backup, which is kept off-site.

What Types Of Files Should Be Backed Up?

The most important files to back up are data files, the files that change on a frequent basis. Periodically, you should also back up the entire system in case of a catastrophic disaster. This periodic backup should include system files that contain specific user information for customized settings and passwords. You may also want to back up software files if you no longer have the original disks. Most backup software provides the option of backing up all files on the drive, the files that have changed since the last backup, or individually selected files.

How Often Should Data Be Backed Up?

Because data files change every time someone enters new information, many companies back up the data files every day (or only those files that have changed) and then perform a complete backup of the entire system on a weekly, bi-weekly, or monthly basis. For your own company, you can determine the necessary frequency of backups by asking yourself how often the data changes and how critical are the different types of data files. In other words, how much data can you afford to lose without causing your business undue hardship?

It may seem that you should back up your files almost continuously, but that isn’t practical. The best strategy is to devise a schedule that works for the majority of your data files. For example, you can schedule a daily backup of new and modified data files and then a weekly backup of all files. If you have critical files that must be backed up more often, you can back up these files throughout the day.

When Should Backups Take Place?

Ideally, you should back up data after regular business hours when employee demands on the network are at a minimum. This off-hours time frame is called the "backup window". Many small companies have an adequate backup window to perform backup jobs at night and on weekends.
However, if your business operates 24 hours a day, 7 days a week (24x7), or if you have employees working in different time zones, you may have little or no backup window. In this case, you must determine a time period when employees will be the least affected.

TIP: If your business operates 24x7, use backup software that has an open file option. This option allows you to perform a backup while the files are in use.

How Long Should Data Be Stored?

How long you store data depends on the type of data and your business requirements.

For data files that change frequently, you should keep only the most recent files. As the previous data becomes obsolete, you can overwrite and reuse the tapes or off-site storage.

For the full set of files on your system, you should store the files in a secure, off-site location such as THETA Backup Solutions remote data center. By having this complete file set, you can recover the entire system in case a disaster destroys the originals.

For certain types of data (tax records, contracts, personnel files, patient records, and so on), you may need to archive data for a specified time period to meet specific legal requirements. In court cases, courts will hold owners and company officers liable for data loss (despite the reason for the loss).

Types Of Backup

There are two different types of backup strategies, so you can decide which method is right for your business. Software applications include options for:

Copying the full set of system files
Copying a partial set of new or modified files
and for Copying selected, individual files.

Most companies use a combination of full and partial backups by performing nightly backups on files that have changed throughout the day, then a full backup of all files on a weekend day.

Full Backups

A full backup copies all the files on the system, the system files, the software files, and the data files. You should perform a full backup on a weekly, bi-weekly, or monthly basis. With a full backup of your data in the THETA RBackup remote data center, you can restore your entire system if a disaster destroys the original files.

TIP: If your data set is small, you could perform a full backup on a daily basis.

Partial Backups

A partial backup copies all files that have been added or changed since the last backup job. There are two main types of partial backups: incremental and differential, summarized in the table below.

TIP: For any crucial files that would be difficult to re-create, you can perform a selective backup at any time during the day. With this method, you don ’t need to wait until the next scheduled backup to copy the crucial files.

What is the difference between incremental backup and differential backup? Which is the best option?

As a backup practice, both incremental and differential backups accomplish the same thing: They allow you to reduce the resources needed to backup data. But how they accomplish this task is different.

If archive bits are cleared after each backup, this is called an "incremental" backup. If the archive bits are cleared only after a full backup, then this is a "differential" backup.

An incremental backup clears the archive bits each time data is backed up. This means that each backup will be small. To perform a restore, a copy of the last full backup and each incremental will have to be restored to get all files to their last known state. In most cases, a full backup will be performed weekly while an incremental backup is performed daily.

A differential backup clears archive bits only after a full backup. This means that daily backups get gradually larger, but restore is easier. A full restore only requires the last full backup and the last differential.

Incremental backup allows for a more granular restore, but differential backups are typically easier to restore.

Incremental Backups

If you need to save time and cost during regular backup jobs, choose a plan that includes full and incremental backups. In this strategy, you perform a regular backup of all files (weekly, bi-weekly, etc.), then a more frequent backup (daily) of only the files that have changed since the last backup session.

This full/incremental backup method means that fewer files need to be copied and less time is required for the backup procedure. However, this method can also make a complete system restore slower if you have created many different incremental backups (one for each day of the week, for example), or if you need to restore only a particular file and must hunt through several different incremental backup sets.. (See “ Which backup strategy is best? ” For more information.)

An Example for Incremental backup strategy:

Differential Backups

If you need to save on restore time and hassle in the event of a disaster, choose a plan that includes full and differential backups. In this strategy, you perform a regular backup of all files (weekly, bi-weekly, etc.), then a more frequent backup (daily) of all files that have changed since the last full backup session.

This full/differential backup method helps the restore process run more efficiently, because only one full backup tape and one differential backup tape are required for a complete restore of the system. However, this method is slower on the backup process because more files are copied daily. (See . “ Which backup strategy is best? ” for more information.)

An Example for a Differential backup strategy:

Which Backup Strategy Is Best ?

Is it better to combine full backups with incremental or differential partial backups? The answer for our situation depends on what factors are most important to you. Do you want to save time and cost on the backup process? If so, you should choose incremental partial backups. Or, is it more important to make the restore process as quick and simple as possible in the event of a disaster? If so, you should choose differential partial backups.

T IP : Most companies perform full/differential backups, because the restore process only requires two backup sets.

The table below highlights the main advantages and disadvantages of incremental versus differential backup strategies

Backup Tips

Finally, here are some additional tips for securing data:

Perform backups without exception. If your employees are responsible for backing up their own data and you are concerned that backups don’ t always happen, centralize the backups across a network. To make backups easier, you can use our THETA RBackup software that performs the process automatically.

After performing a backup, use the backup software to verify that the backup completed successfully. We recommend that you restore one or two unimportant files to be sure that the backup is valid.

Run a good antivirus software on your computer system to prevent viruses from being transferred onto your backup media.

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