Although he said cost is not the only down side. “Active-active recovery solutions do not account for user error. They are garbage in garbage out, and in the event of this type of an outage, you need to have something that is tracking point in time consistency of the data to recover back to. The GitLab outage from a few weeks ago is a great example of this,” Foster said.
“There could be any number of mission-critical applications worth the protection of active/active redundancy, the trick is determining those that merit the expense,” said Steven Hill, senior storage analyst with 451 Research. “It’s important to remember that a good DR/BC plan calls for a broad assessment of a company’s key business priorities; the personnel, data and applications necessary to support them; and the cost of alternative options available to replace them — all weighed in a cost/benefit analysis against the risk of loss and likelihood of a critical business interruption.”
Pros and cons
Don Foster of Commvault offers the upsides and downsides of an active/active architecture.
- Fast or instant recovery – often without any downtime
- Duplicates the production environment to ensure service portability regardless of the infrastructure outage
- Often is provided as a part of the application offering (Oracle RAC, DAG for Exchange, etc.)
- Easy to operate once set up
- Expensive – Must duplicate the infrastructure and always have it running. This makes this scenario very expensive in the cloud
- Does not recover in the case of data corruption (non-infrastructure event)
- Requires more solutions to truly “protect” a service or application from an outage of any type
- Does not provide versioned copies of data
- Hard to set up and maintain for a complex service or application
Dark disaster recovery is more cost effective, is typically data outage focused, and can be very complementary to the built-in active recovery services, Foster noted. The infrastructure would be highly available with data copies tracked with real-time and versioned point-in-time references to solve any outage issue that may arise.
ScaleArc’s CEO Justin Barney believes an assessment of the costs for an active-active architecture must take into account the potential losses of downtime. “Active/active operations do cost a bit of a premium – about 20 percent in hardware and software costs. But those additional costs don’t include offsets from sources such as revenue losses averted because of avoided downtime. Overall, the perspective that active/active operations are warranted only for organizations that can’t afford downtime is true,” he said.
Barney said with demand for continuous availability dominating nearly every industry, active/active operations clearly provide the best mix of advantages.
There’s new data showing that the backup systems and processes enterprises have relied on the most to ensure business continuity/disaster recovery might actually be hurting not helping when it comes to preventing major outages, according to Barney. “This is important now because these disaster recovery systems are no longer meeting the needs of organizations that must achieve ‘continuous availability.’”
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