Every disk drive that is manufactured will eventually fail. While most disk drives are designed to last from three to five years, any disk drive can fail at anytime. In addition to disk hardware failures, there are other causes for data loss, such as viruses, accidents, human error, and disasters. Any data that is stored on any computer can be lost without warning. Therefore, every computer owner should have a strategy to backup and recover data.
Six questions you should consider when designing a backup and recovery strategy:
- How much is your data worth? Your backup and recovery strategy will be dependent on the value of your data. It can be difficult to assign a fixed value to data. One approach is to think through what it would mean if your data was permanently lost. How much would your business lose? Once you have an assessment of the consequences of losing data, you will have some idea how much it is worth to prevent that loss. If a loss of data could destroy your business, then you shouldn't fret over spending a few hundred dollars a year to protect it.
- How much downtime can you afford? Assume your data is reliably backed up everyday. If your data is destroyed, how much will it cost if you are down for a day? Can you limp along for a couple of days without significant financial losses? In a lot of cases, being without the data for a few days may not be devastating as long as the data is recovered within a reasonable time period. In other cases, being down for a day would be a major loss of revenue. If your situation calls for minimal downtime, then you may need more than data backup. You may need an entire hot recovery site, complete with computers and replicated data ready to take over your operation in a relatively short time.
- What kinds of losses do you want to protect against? There is a difference in protecting against a disaster such as a fire, flood, or storm, and protecting against accidental erasure. Being able to restore deleted files only requires that you have a copy of the file on a cd or other media. Protecting against a disaster requires that you store a copy of your data off-site. In some cases multiple copies of backup data are made so that one copy can be moved offsite for disaster recovery purposes and another copy remains on the premises for the purpose of restoring deleted , corrupted or otherwise mishandled files.
- How often does your data change? If your data changes only once a month, then you probably only need to backup your data once a month. However, most business have data that changes daily, if not constantly, throughout the day.
- How long do you need to retain your backup data? The answer to this question may be dependent on your industry requirements. You may be required to comply with federal, state, or local laws relating to records retention. You should also consider the circumstances particular to your business. In some cases, data may be completely useless and invalid after a couple of days and would never be restored after a certain amount of time has passed, for example; a news website. In other cases, there may be reasons to retain backup data for many years.
- How much security do you need? The security requirements of backup data should not be overlooked. Backups of sensitive data, such as credit card numbers or medical records, may require encryption. When sensitive data is backed up and stored offsite, security becomes an important concern and must be integral with the backup and recovery strategy.
The answers to the above questions are needed to form a strategy that is sufficient for your needs. Effective data backup and recovery systems don't have to be expensive. But if your business depends on having your data available at all times, then the cost of a data backup and recovery system may not be a factor in your strategy.
If a few hours of downtime can have a serious impact on your business, then you may want to consider a replication strategy and hot standby systems. Depending on the severity of the potential impact, it may be necessary to maintain a disaster recovery site. If a day of downtime and the loss of up to one day of data could be managed so that your financial losses are minimal, then daily data backups are probably sufficient. At a bare minimum, all businesses and most home computer users, should have a backup and recovery plan that keeps copies of all important data in an offsite location. Your retention requirements will be a big factor in determining how much media or backup storage space are needed.
In most cases, the cost of backup and recovery systems will be easily justified when the cost of a data loss are considered. Attempting to save money by delaying a full backup and recovery plan is foolish. Consider the first paragraph of this article, you don't know if your loss will be today, tomorrow, next month or next year. Failing to implementing an effective data backup and recovery plan is equivalent to driving an automobile without insurance.