SharePoint and SQL Server replication

For several versions now, SQL Server has included the ability to replicate content between databases. In the quest to make SharePoint highly available, you might be tempted to investigate SQL replication of SharePoint databases using this mechanism.
Unfortunately, SQL Server replication is not supported with SharePoint. If you are seeking to make your SharePoint environment highly available, look instead to other technologies such as Windows clustering and SQL Server database mirroring.
SQL Server transaction log shipping may also fit the bill for you if your requirements are more tolerant to data loss and down time.
Alternatively, there are third party products which can perform replication in SharePoint-friendly fashion.