Backup and archive tapes typically hold a complete copy of all electronic data used by a company. A backup tape will hold a complete copy of all e-mails stored before and up to the day the copy was made, along with all business documents, finance information, operational transactions and all of the computer programs that make the system run. Tapes will contain a snapshot of the business allowing full analysis of any particular period and detailed comparison between any two or more periods.
Backup tapes will retain copies of e-mails that a user has marked for deletion but have not been ‘purged’ by the systems administrator. This procedure is often only run on a monthly basis which means there may be an ongoing record of communications that the user believes was removed some weeks before.
Types of Backups
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 set on tape, you can restore your entire system if a disaster destroys the original files.
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 below.
Incremental Backups
Incremental backups include files added or changed since the last full or partial backup. Organizations may 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 backup tapes (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 tapes.
Differential Backups
Differential backups include files added or changed since the last full backup. Organizations 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 backup tapes (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 tapes.
BACKUP TYPE ADVANTAGES DISADVANTAGES
Incremental (all new or modified files since last full or partial backup) Faster backup time because there are fewer files. Reduced wear on backup device and tape. Fewer tapes may be required. Slower restore times because there may be more than two tapes required (the full backup tpe and each incremental tape.) Higher cost of downtime in a system disaster.
Differential (all new or modified files since last full backup Faster restore times because there are only two tape sets required (the full and differential backup tapes). Lower cost of downtime in a system disaster. Slower backup process because more files are copied. Increased wear on backup device and tape. More tapes may be required.
Frequency of Backups
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.
Why Incremental Backups
The real benefit of incremental backups lies in the fact that even if the user has deleted the e-mail and the IT administrator has cleaned up the deleted messages, then simply going back to the last tape created could yield the information you need.
When to Backup Tapes
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.” Most small companies have an adequate backup window to perform backup jobs at night and on weekends.
eMag Solutions offers over 40 years of experience and expertise with backup tapes, providing restoration, recovery, conversion, stacking, duplication, and destruction services for any kind of backup tapes, along with other media such as optical platters, hard drives, disks, and portable media. For more information, please contact us, and to view a list of supported media formats, please visit supported media formats.
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