There are many reasons to have a backup and restore policy. Your data is subject to failure because of failed components, natural or man-made disasters, or data corruption.
Sometimes data loss is beyond your control to prevent, but with a backup and restore plan, you can restore your data.
Customize backup and restore policies to take into account your situation, what data needs to be saved, how often, and how much time and effort is used to restore it. Your policy specifies the procedures and practices that meet your restoration needs.
Backups are an investment of time, money, and administration effort, and they can affect performance. However, there’s a clear return on investment in the form of data integrity. You can avoid substantial financial, legal, and organizational costs with a well-planned, well-executed backup and restore policy.
There are three kinds of restoration needs:
Restoring a deleted or corrupt file
Recovering from disk failure (or catastrophic file deletion)
Archiving data for an organization (financial, legal, or other need)
Each restoration need determines the type, frequency, and method you use to back up your data.
You might want to keep daily backups of files. This enables quick restoration of overwritten or deleted files because any individual file can be restored the following day.
There are other levels of granularity. For example, you might need to restore a full day’s data. This is a daily snapshot-level granularity: you can restore your organization’s data as it was on a given day.
These daily snapshots might not be practical to maintain every day, so you might decide to keep a set of rolling snapshots that give you daily snapshot-level granularity for only the preceding month.
Other levels of restoration you might want or need could be quarterly or semiannually.
You might also need archival storage, which is data stored only to be accessed in uncommon circumstances. Archival storage can be permanent, meaning the data is kept for the foreseeable future.
Your organization must determine the following:
What must be backed up?
What shouldn’t be backed up (as per organization policy)?
How granular are the restoration needs?
How often is the data backed up?
How accessible is the data: in other words, how much time will it take to restore it?
What processes are in place to recover from a disaster during a backup or restore?
The answers to these questions are an integral part of your backup and restore policy.