Database Protection Turns a Corner

The seemingly never-ending quest for cost-effective, reliable Oracle data protection and availability has taken a turn for the better. At least two vendors are delivering a new capability that integrates the features of disk-to-disk backup and continuous data protection (CDP) without increasing storage capacity requirements.

This new development can be described as the active target technique. Implementations are currently available in NetApp's Open Systems Snapvault and Syncsort's Backup Express.

Let's take it from the top: The architecture of an active target is similar to that for traditional backup. First, there are IP- or SAN-connected servers directing data to a backup server that has an active target software module installed. Attached to the backup server is a disk array. This disk serves a LUN to the backup server, so it must attach either via iSCSI or Fibre Channel.

For basic recoveries using an active target technique, this configuration is all you need. For some of the advanced features described later in this article, the link between the servers being backed up and the backup server must be a block-level iSCSI or FC SAN connection, not merely a LAN one.

The basic problem addressed by the active target approach is that backup applications, even when backing up to disk, tend to store the data that they are backing up in their own file format, which essentially bundles up a set of files into a larger file. Before we had disk as a viable backup target, this was a logical way to achieve good performance when backing up to tape. However, when backing up to disk it makes less sense, because the data in backup format must go through a recovery process before it can be used by the application.