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As continuous data protection (CDP) is integrated into backup environments, implementations with other backup protection programs may become complex.|
continuous data protection (CDP) software is primed to tackle enterprise high-availability requirements. As companies seek to eliminate or drastically reduce backup windows and to create faster point-in-time recoveries for more mission-critical apps, CDP software has become a viable alternative to traditional backup software and storage system-based replication software. But with multiple points where CDP software can be integrated in the storage infrastructure, and the emerging linkage of CDP with backup applications, organizations may need to tackle lengthy and potentially complex CDP implementations. This article focuses mainly on CDP products from vendors who sell CDP and backup software.
How CDP products capture and copy changed data, and the recovery options they offer, varies widely:
- Desktop and laptop CDP products are engineered to work with infrequent network connectivity, and some programs allow users to recover their own files.
- CDP products for servers presume uninterrupted network connectivity (although they can handle service disruptions) and centralized management.
- FC SAN-attached CDP
Most enterprise-class CDP products offer the following essential features (see "CDP key considerations," below):
- appliances assume clustered servers, hundreds of LUNs and high data change rates.
- Backup software integration. When integrated, backup software can schedule CDP snapshots (called replicas) that the backup software can use to back up, catalog and recover information. Without integration, companies need to manage CDP as a standalone product.
- CDP consistency groups. Consistency groups ensure that if one database is spread across multiple volumes or LUNs, all CDP-managed volumes are kept synchronized at all times to create recoverable database images.
- Database integration. CDP host agents integrate with the database and support the creation of transaction-consistent database images. Without this level of integration, the CDP application can only create crash-consistent images that require a database administrator to complete the database recovery.
- Recovery options. CDP software may allow companies to recover from replicas, select point-in-time recovery points, do file- or block-level recoveries, and even present virtual LUNs through the CDP appliance on which applications can operate.
- VMware server support. FalconStor Software Inc.'s CDP Virtual Appliance for the VMware Virtual Infrastructure converts VMware OSes into its virtual CDP appliance. Other vendors are planning to offer agents for VMware's hypervisor that support recovery of all OSes hosted by the ESX server.
Click here for a sampling of
CDP key considerations (PDF).
This was first published in September 2008