Disaster / Data Recovery
Disaster and data recovery are subjects not often given much thought by some business owners. They should be.
In the most catastrophic of scenarios, if you lose your database(s), you will soon be out of business. Industry research substantiates what I am saying to an alarming degree: Data Loss Statistics.
There are multiple reasons why data recovery should be a priority:
- In the event of a catastrophic database or hardware failure, databases must be restored to put a company back in business, since without your database, you’re out of business.
- In the event of database corruption, the affected database(s) must be restored to a point in time before the corruption occurred.
- Occasionally, an employee or an incorrectly written SQL query will inadvertently and mistakenly delete data from a database.
In all cases, the first question becomes, “How, and how fast can we get the data restored?”
- If you have direct attached storage, traditional restoration of SQL Server database backups is the answer. This can take time, especially in the case of a large database, but it must be done and the time must be taken.
- If you have a SAN, some SAN manufacturers provide software and procedures to perform synchronized database data and log file backups as “snapshots”, and therefore guarantee database integrity at the moment a snapshot of the database(s) is(are) taken. In a database restoration scenario, these SAN snapshots have the advantage over traditional database backup restorations of taking mere minutes instead of hours.
There are other, very important questions that should be answered BEFORE a data loss and/or catastrophe occurs:
- How much data can your company afford to lose?
- How long can your company afford to be "down"?
- Which is more important, being "up" or recovery of data? There is a precise tradeoff in elapsed time between the answers to the 2 components of this question.
- How far back in time should a company retain database backups and for what reasons?
- Are there legal reasons to have database backup archives, potentially going back in time for years?
- How much data can a company afford to retain? Disk space costs money. Are tape backups a good solution? Is tape media and technology reliable enough to bet your business upon it? Is recovery using tape backups fast enough to satisfy the need for your business to be back online?
I could provide more business related questions but I’m sure my point is well made. Data recovery is not a technology issue, it is a business issue, and business questions need to be asked and answered to drive the production of a viable data recovery policy and plan for implementation.
A company's data recovery policy needs to be well documented. The plan for execution of data recovery needs to be well documented and tested. In a time of crisis, encountering unexpected impediments to successful data recovery should not be a possibility.
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