Introduction to Tape Rotation

A common question asked by businesses is how often to backup information and what type of information should be backed up. Regardless of the size of your business, it is important to back your data up regularly to prevent unneeded loss. Some data loss is a bigger deal than others, so let's go through the different types of things your company may need to backup. There are two main types of backup: full and partial.

Full Backup

A full backup should typically be made every one to two weeks or as your business sees fit. A full backup will include everything on your system from files and software to databases and operating systems. The full backup is the mother-load; it is the safety net to use should anything disastrous happen on a large scale. These backup tapes should be stored offsite at all times and should be part of a rotation. On a biweekly full-backup schedule, for example, you would have tape A stored offsite while tape B is used to backup the last two weeks data. After two weeks, you would backup everything on tape B and swap it out with tape A and so on. This ensures that at any given moment you have a complete backup of everything on your system safely stored offsite.

In addition to weekly or bi-weekly backup, full backups should be made monthly and stored offsite as well. Ideally, you should have a backup tape for each month of the year which is rotated out only once per year. For example, in January 2012 you would backup your entire system over the January 2011 tape and so on. It is like a macro-incremental backup.

Partial Backup

Don't underestimate the importance of regularly backing up changing data. Having your entire system backed up every week or two is great in case of a big problem, but it is still a massive headache if you don't have your  company's work in progress backed up regularly. Partial backups should be run daily and stored in a safe location. Partial backups protect against smaller disasters which result in data loss but not a massive overhaul of your system. We all know how frustrating it is when you forget to save something you are working on and your computer crashes, losing everything. Imagine if that happened to everyone in your company all at once. Partial backup will save any changed information since the last designated backup. There are two types of partial backup.

1. Incremental Backup. Incremental backup is a form of partial backup in which all data that has been changed or modified since the last incremental backup is saved. If you run an incremental backup at the end of each work day, you would end up with five backup tapes, each of which would have data that had changed from the previous day. This requires more tapes than other forms of backup, but gives you more security as well.
2. Differential Backup. Differential backup is a lot like incremental backup in that you want to run it every day; however, rather than backing up all changes from the last partial backup (the previous day) it backs up all changes from the last full backup. The nice thing about this method is that you only have to have one or two tapes for differential backup rather than one for each day of the week as with incremental backup. You can save over the previous day's changes on the same tape and all changes since the last full backup will be saved. The downside is that you loose progressive portions of projects etc. and backup tapes will wear out faster.

data obtained from http://www.exabyte.com/support/online/documentation/whitepapers/basicbackup.pdf

Where Do I Store My Backup Drives?

The simple answer: a third-party offsite storage facility.

Offsite storage of data backup is essential to the security of any information for businesses big and small.

Why Offsite?

Ease of access is the main “reason” businesses choose to store their data backup onsite. While seemingly convenient, onsite storage practices are extremely dangerous. While this type of storage may protect your business from viruses, hacking, or other software and hardware related problems, onsite storage does not protect from disasters and other hazardous situations. In the event of fire, theft, or other disaster both your primary and backup data may be destroyed, and all the cost and planning of your backup system will have been in vain.
Offsite storage protects your business from both internal and external errors and events. As far as ease of access is concerned, many third-party storage facilities promise same-day delivery of any portion of your backup at no additional cost.

Why a Third Party?

The importance of storing data backup at a third party location would take up blog posts for weeks to get through (which we will do). But we’ll sum up some basics today.

1. Security and Legality
   Some companies hand backup tapes to a secretary or other employee to take home each night. While there are some obvious security issues with this process, there are legal problems associated with it as well, primarily the fact that the practice of any employee taking backup data home with them is completely illegal. A company that loses a backup tape being stored in such a manner is considered negligent and loses all insurance protection associated with the loss. This can result in huge losses, lawsuits, and legal trouble. In short, just don’t do it.
2. Cost
   Provided backup data is not being sent home with an employee, another means of data storage needs to be provided. As we’ve noted the importance of offsite storage, trying to set up your own offsite storage facility is expensive. Backup data should be stored according to particular standards and procedures which are not available at a typical storage unit. Not only is it a headache to set up your own self-storage unit, the cost of self storage far exceeds that of a storage facility specialized in data storage and records management. The main issue with cost is that a business using a self-storage unit cannot rent a small enough space to make it worth it. Specialized records management companies, on the other hand, store and price based on units, not square footage. For example, if you only have five backup tapes, you can store them at a records management facility for less than a dollar per tape. However, if you are using a self-storage unit, you’ll end up paying for an entire 8x8 unit to store five tapes!
   
3. Specialization
   Self-storage units are not equipped with the right technology to safely store data backup. Water damage, climate control, security, and accessibility are all problem areas associated with self-storage units. Records management companies are specialized in data backup storage and its proper care. Their facilities are required to meet certain standards specifically designed for data backup storage.

Ok, so let’s summarize the importance of third-party offsite storage for data backup.

1. Less expensive
   
2. Less liability/more protection
   
3. Easy to access
   

In my opinion, it’s a no-brainer. Data backup should always be done by a third party. It will save your business time and money.