Disaster recovery glossary of terms
When doing research about disaster recovery, you may come across some key terms that are unfamiliar. The following is a glossary designed to help you navigate the waters of disaster recovery.
Disaster recovery: A subset of business continuity, disaster recovery is how your organization will recover and maintain operations during and after a disaster has been declared. Disasters can come in all forms, from fires and floods to electrical outages, cyber attacks, and administrative failures. Disaster recovery plans are critical to any organization, but it’s important to remember that there are many facets that keep a business running, and to plan outside the scope of IT.
Business continuity: The concept of business continuity a series of procedures and protocols your business has in place to keep all operations running smoothly. What do you do if there is a fire? How about if your CEO suddenly has to step down, or there is a bout of flu, and half of your employees call in sick? Or if your website crashes? Each of these potential scenarios should be addressed in a business continuity plan, starting with a business impact analysis or risk assessment analysis to identify and minimize threats to the organization.
RPO/RTO: RPO stands for Recovery Point Objective, and it’s the specific amount of time that a business decides it can survive a period of data loss. When you decide how often you need to back up your data – whether that’s every five minutes, or every five hours – that is your RPO. RTO, on the other hand, stands for Recovery Time Objective, and is the most amount of time a business can afford to have their systems unavailable. How long can you have your systems down before it negatively affects your organization?
Cold/Warm/Hot site: These are different types of recovery sites, and each level signifies the amount of time it takes to fail over to and start operations from. With little hardware, a cold site takes the longest to get operational, while a hot site can be failed over almost instantly with all infrastructure components up and running.
Failover: When you switch from your production to your recovery site, that’s a failover. Essentially, when your production site fails, you go over to your recovery site. When your production site has been repaired and you’re ready to return, you execute a failback.
Continuous data replication: There are two types of continuous data replication: True and near. True continuous data protection (CDP) is real time replication of data as it is being written to disk. Each time a change is made, it is copied to a separate disk when that change is made. With continuous data protection, you can achieve minimal RPO and ensure the data at your recovery site is as up to date as possible with your production site.
Near CDP is a similar concept; however, it uses snapshots to recover to a certain point in time. Near CDP has specific points of recovery that are much more frequent than traditional backup (say, every hour instead of every 24), but you don’t have the ability to return to any point in time you wish, as you can with true CDP.
DRaaS: Disaster Recovery as a Service, or DRaaS, is a method of disaster recovery where infrastructure, personnel, testing and other associated costs and equipment is outsourced to a third-party provider. It consists of a replication product (continuous data protection), an offsite backup product (point-in-time recovery), a disaster recovery plan and vaulting that plan so you can access it in an emergency. A DRaaS provider should also work with you to test your infrastructure, workloads, and all associated components of your applications, including the applications themselves.
Backup: Data backup is categorized into onsite and offsite, and there are many different levels of backup within those two categories. They include how often you decide to back up your data, and what level of granularity you want. However, no matter what your backup plan calls for, the concept includes having a copy of your data stored either onsite or offsite. If you need quick access to your data and can’t wait for it to be restored from an offsite location, then onsite backup is for you. However, if you’re looking for data protection, offsite data backup is more reliable if something happens to your production site.
High Availability: High availability is when your environment, whether production or recovery, has a high amount of uptime, or availability. The higher your availability, the less likely you will be subject to downtime. Some businesses require a certain amount of availability – measured in nines (ie 99.999 percent)—in their SLA with service providers.
Mirroring: When data is copied exactly from one site to another. Mirroring is done in real time, and can be done at an offsite facility, or onsite. If done offsite, mirroring is a handy disaster recovery tool that allows an organization to quickly recover the most up-to-date version of their data from a completely different location.