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Preventing data loss
The impact of data loss is generally reflected in the recovery point objective (RPO) for an application or data set. You may find that much of your data is protected by previous backup or archive copies. This is especially true for historical, fixed-content data that's kept online for easy reference and comparison. Previously backed up copies provide full protection against data loss, so mirroring and replication may be expensive overkill. For these applications, an acceptable RPO might be 48 hours or more.
In contrast, the most recent OLTP activities generally haven't been captured by a periodic backup process, so they'll require stronger protections. For critical transaction-processing applications, an RPO of an hour might be too long. However, since very low RPO values are expensive to achieve, it's important to ensure that the objectives are applied appropriately to specific data sets.
In addition to preventing data loss, businesses must ensure that critical applications and data sets are restored quickly after an outage. The time allowed for recovery is specified in the recovery time objective (RTO) for each application or data set. Some transaction-processing applications may need to be recovered within a few minutes to avoid losing business or damaging customer satisfaction. In contrast, some project-oriented applications and data sets, such as software development, test systems or marketing analysis databases, might tolerate
This was first published in June 2006