How Does Bandwidth Affect Your Disaster Recovery Plan?

How Does Bandwidth Affect Your Disaster Recovery Plan?

May 8

We’ve already discussed why you need multiple backups in diverse locations in your disaster recovery plan, including:

But as cloud computing becomes cheaper and more secure, you may be wondering: “Do I really need to keep a local, offsite backup image of my critical information should, G-d forbid, something happen at the office? Won’t the cloud serve those needs just as well?”

Well, it depends. How much time do you have?

Cloud-based backups are always going to take longer to download and implement because their bandwidth speeds can’t compare to a local backup. I recently spoke with Steve Snyder, technical marketing manager at StorageCraft, and he discussed the differences in bandwidth speeds among commonly used “pipes” within a data center or IT environment:

  • Gigabit Ethernet (GbE): 1Gbps-10Gbps
  • USB 3.1: 10 Gbps (doubles the speed of USB 3.0)
  • Latest Wireless Standard, 802.11ac: 7Gbps
  • T1 Line: 1.5Mbps

Steve said these numbers rarely pan out in real-world situations:

“Because of latency and imperfections in your cables, routing issues, and things like packet loss, you won’t be transmitting at those optimal speeds. You’re more likely transmitting at around one-half to two-thirds of that ideal speed.”

Most businesses can’t afford to wait the amount of time needed to download a backup file image from the cloud to replace a failed hard drive, a patient accidentally pouring coffee on a doctor’s laptop, or a building fire. Scenarios such as these rarely excuse businesses from, say, maintaining their online storefront or from accessing a patient’s EHR.

Let’s say you need to restore 2TB of data from your backup file because of that failed hard drive. If you connect a new recovery target to a DAS (direct attached storage) backup with a USB 3.1 cable, the optimal amount of time for transferring that backup would be about 27 minutes. But as Steve pointed out, you probably won’t get that ideal speed: “You’ll probably look at it and say, ‘You know what? I’ve been getting one-half of that in terms of throughput,’ so we’re looking at something more like 54 minutes.”

While 54 minutes is not exactly instantaneous, it is way faster than trying to download the same image from cloud storage. In the U.S. at least, ISP download transfer rates range from 5–15Mbps in cites and only about 1–5Mbps in rural areas—and that’s assuming you’re not dealing with issues such as:

  • Latency
  • Shared bandwidth with others on your ISP
  • Throttling of processor speed on the part of the cloud provider

According to Steve, AWS (Amazon Web Services) will only allow you to download a certain amount of data at a time before it throttles the speed. To continue to download your image at that higher (albeit slow relative to local storage) speed, AWS will charge you more for it.

Cloud backup should definitely be a part of your backup and disaster recovery plan, but it should really be used as your last resort. If you and your organization are unfortunate enough to find yourself in the midst of a catastrophic EF5 multiple-vortex tornado like the one in Joplin, Mo., a Northridge-style earthquake, or a hurricane on the level of Superstorm Sandy (let alone Hurricane Katrina), of course, you want the security of knowing your information can still be accessed via the cloud.

It just shouldn’t be your only resort, not yet anyway. For anything but a full site disaster, the time it takes to recover will likely be more than you want.

Photo Credit: Arbron via Compfight cc