Cloud can shorten the time it takes to recover from a disaster from as long as weeks to 24 to 48 hours, in some cases. Still, recovery within a couple of days isn't nearly as fast as some shops want. In disaster recovery parlance, that recovery time objective (RTO) is too long. And even if you can boot the cloud-protected VM up quickly, it may not be as up to date as you'd like because the time period between the last backup and the outage is too great. In other words, the recovery point objective (RPO) might not be acceptable.
Enterprises must look beyond cloud's shortened recovery time to these RTO and RPO metrics to find the true value and success of your disaster recovery plan. In some cases, however, cloud DR providers pride themselves on including this service as part of their offering.
RTO, RPO revisited
Virtualization management software provider HotLink had three servers die in the span of one week several years ago, recalled Lynn LeBlanc, HotLink Corp., CEO. Those server images were already up in Amazon Web Services as part of HotLink's engineering efforts, but they weren't particularly current -- the firm only sent changes to Amazon once a day -- and couldn't simply be powered on without suffering some serious data loss. HotLink therefore had to recover from a more current data source, which took many hours.
"If we had been capturing those changes as we went along, we could have been up and running in the matter of a couple of minutes," LeBlanc said.
Disaster recovery and the cloud
Part 1: Cloud computing advantages bring disaster recovery to the masses
Part 2: RTO, RPO metrics find the true value of a cloud DR strategy
Part 3: In the cloud DR market, all eyes are on the enterprise
Part 4: DRaaS means disaster recovery doesn't have to break the bank
In order to get to a better RPO, the company began synchronizing its servers on a more continuous basis. Thus was born HotLink DR Express. The product combines VMware's native changed block tracking function to keep protected VMs current in the cloud, plus HotLink's patented "transformation engine," which allows users to run and manage a VMware VM on AWS in real time, as part of an on-premises VMware vCenter domain.
Indeed, replication software of some form or other is a key component of many cloud DR offerings. As part of its To-Cloud Recovery as a Service offering, Bluelock relies on software from Zerto, a VMware native replication tool that plugs in to VMware vCloud Director or vSphere. Through Zerto's copy-on-write replication, Bluelock is able to offer sub-minute RPOs, said Pat O'Day, Bluelock chief technology officer.
The appeal of DRaaS
But for others, not having to figure out the subtleties of RTOs and RPOs is the appeal of cloud DR. That's especially true for smaller organizations that did not have access to high-end DR services in the past, said Rachel Dines, senior analyst at Forrester Research.
"Orchestrating your own failover is a lot more complex than people realize," Dines said. "It's one of those things: People start out with the intention of doing it themselves but shift directions."
Dines said she's seen a surge of Disaster Recovery as a Service (DRaaS) providers recently whose claim to fame is making cloud DR super easy. According to a recent Forrester report, leaders in the DRaaS market include SunGard, iLand, IBM, nScaled Inc., Verizon Terremark, EVault and Axcient Inc. They provide not only the software and cloud platform, but also services to assist customers during implementation and failover.