Backup vs replication: How reliable is replication compared with backup?
Data replication and traditional backup both create a copy of your source data, but what are the key strengths and weaknesses of the two methods?
Backup creates a copy of your source data or changes to it, usually at the end of the day, and provides you with access to versions of files that you can roll back to. Replication, on the other hand, creates a copy of your data in real time or near real time. Replication, therefore, is likely to provide a more up-to-date copy of your data than a backup.
Backups, however, do provide a complete copy of all files at the time the backup was made. By contrast, if replication is used simply to mirror from site A to site B, deleting a file at site A would mean the file would also be deleted at site B. So, replication needs to be combined with continuous data protection or snapshot technology to create recovery points to roll back to.
On the plus side for replication, however, is recovery time. It may take considerably longer to recover a whole site from backups compared with from a replication copy, and this makes replication eminently suitable for disaster recovery scenarios.
Within their respective limitations, both are reliable as long as monitoring and reporting is in place to ensure quick resolution of issues before they impact operations.
This was first published in September 2011