Although replication provides near real-time data protection and ease of use and maintenance, it is extremely resource-intensive. It can also replicate naturally occurring system errors to your off-site location, which can immediately eliminate the hoped-for protection offered by off-site data storage.
A better approach to off-site data storage is vaulting, which uses a less real-time technology but allows a level of file system integrity not found in a replication environment. Vaulting operates at the file-level, where the built-in operating system checks and balances on file system integrity are allowed to operate. This ensures that data stored in the off-site environment is accurate, complete and able to be used for recovery in the event of a disaster. Additionally, the resource requirements are minimized since the vaulting is provided by a secondary dedicated system, not the active servers themselves.
Today’s best practices suggest that IT professionals should look for a vaulting system that moves only changed data, not the entire backups or original data source. This type of system minimizes bandwidth requirements and maximizes backup windows. You should also look for dedicated, special purpose hardware to support your vaulting solution, preferably hardware and software that are fully integrated by the manufacturer with optimized communication layers to keep the vaulting efficient.
In the case of either replication or purpose-built off-site vaulting, be sure to check compatibility with your local network infrastructure, including switches, routers, NICs and other components. There are hidden complexities in virtually all networks, and these can cause failures with either approach.
Finally, as with virtually every other disaster recovery plan component, test relentlessly. Only successive and consistently successful tests can provide the necessary level of confidence that the backup systems will be there in the event they’re needed.