Replication over WAN: Your DR is only as Good as Your Last Packet
Recovering data quickly in the event of an emergency is inherently dependent on your network. Replication simply won’t work if the WAN links connecting production and DR sites are down or weak. As the discussion around DR moves to an “always-on” approach, where replication RTO/ RPO targets are minutes and even seconds, networks are feeling the heat.
This week, VMWare’s infrastructure product manager Gaetan Castelein was interviewed for a great post on ReadWriteCloud. He notes the DR industry’s move from pure disaster recovery to disaster avoidance. “When you talk about the need to have more resilience, what we’re seeing is, people now want to go beyond just disaster recovery to get also into the field of disaster avoidance,” he explains. The instigator of this change has been the growing number of occurrences when companies have seen a hurricane coming in on the radar, and rolled the dice.”
But Mr. Castelein notes one difficulty of a disaster-avoidance, proactive approach to DR. “Distance continues to play a role in the equation of mobility between data centers, because even the smallest degree of latency multiplied by a few terabytes becomes an unmanageable quantum of time. And the bigger your enterprise is, the broader the roadblock becomes.” The article goes on to mention that, “Castelein concedes that this problem is not solvable for big businesses right this moment.”
Attention big business: we think it is solvable now.
With hypervisor-based replication from Zerto, network resiliency and optimization are not an afterthought, but built into the product. We’ve built networking and WAN optimization features into Zerto Virtual Replication in the following ways:
- Prioritization: Each application has a priority setting that dictates its WAN priority, enabling the administrator to differentiate between different applications and ensuring that tier-one applications get first dibs on the network.
- Resiliency and Compression: Zerto has a built in patent-pending compression mechanism and WAN resiliency, capping WAN bandwidth between sites. This includes automated rollback of uncompleted actions.
- Outage Recovery: Even though Zerto replication is continuous and does not rely on snapshots, in the case of WAN deterioration, Zerto does recover a block of changes and ship the changed set when the outage is resolved. In a prolonged outage, the memory footprint created to recover the block of changes is minimal and syncing back up after the WAN is restored does not negatively affect the production environment.
So, today, even large enterprises can proactively manage their data center effectively — despite network instability. And it’s already happening. One of our customers, Woodforest National Bank, achieves proactive disaster avoidance by failing over their entire data center to a secondary site prior to hurricane season. You can read the full Woodforest case study here.