What can I expect to learn from this blog?
This blog offers an introduction to the 4 types of Backup and DR solutions that AWS has to offer. Enterprises use a mixture of these techniques. If you understand the basics of cloud computing, and want to know how you can protect your data from a disaster, to ensure business continuity; you have come to the right place.
What happens when you don’t have the right DR system !
What is a disaster?
A disaster can be defined as any phenomenon that disrupts business continuity. It is not only any natural calamity such as an earthquake or a flood, it can be any hardware or software failure, a network or power outage, physical damage to a building like fire or human error.
What is Disaster Recovery?
Our data is the most precious asset that we have and protecting it is our top priority. Creating backups of our data to an off shore data center, so that in the event of an on premise failure we can switch over to our backup, is a prime focus for business continuity. As AWS says, ‘Disaster recovery is a continual process of analysis and improvement, as business and systems evolve. For each business service, customers need to establish an acceptable recovery point and time, and then build an appropriate DR solution.’
Backup and DR on Cloud reduces costs by half as compared to maintaining your own redundant data centers. And if you think about it, it’s really not that surprising. Imagine the kind of cost you would entail in buying and maintaining servers and data centers, providing secure and stable connectivity and not to mention keeping them secure. You would also be under utilizing severs; and in times of unpredictable traffic rise it would be strenuous to set up new ones. To all these cloud provides a seamless transition reducing cost dramatically.
4 standard Approaches of Backup and Disaster Recovery using Amazon Cloud:
1. Backup and Recovery: To recover your data in the event of any disaster, you must first have your data periodically backed up from your system to AWS. Backing up of data can be done through various mechanisms and your choice will be based on the RPO (Recovery Point Objective- So if your disaster struck at 2 pm and your RPO is 1 hr, your Backup & DR will restore all data till 1 pm.) that will suit your business needs. AWS offers AWS Direct connect and Import Export services that allow for faster backup. For example, if you have a frequently changing database like say a stock market, then you will need a very high RPO. However if your data is mostly static with a low frequency of changes, you can opt for periodic incremental backup. Once your backup mechanisms are activated you can pre-configure AMIs (operating systems & application software). Now when a disaster strikes, EC2 (Elastic Compute Capacity) instances in the Cloud using EBS (Elastic Block Store) coupled with AMIs can access your data from the S3 (Simple Storage Service) buckets to revive your system and keep it going.
2. Pilot Light Approach: The name pilot light comes from the gas heater analogy. Just as in a heater you have a small flame that is always on, and can quickly ignite the entire furnace; a similar approach can bethought of about your data system. In the preparatory phase your on premise database server mirrors data to data volumes on AWS. The database server on cloud is always activated for frequent or continuous incremental backup. This core area is the pilot from our gas heater analogy. The application and caching server replica environments are created on cloud and kept in standby mode as very few changes take place over time. These AMIs can be updated periodically. This is the entire furnace from our example. If the on premise system fails, then the application and caching servers get activated; further users are rerouted using elastic IP addresses to the ad hoc environment on cloud. Your Recovery takes just a few minutes.
3. Warm Standby Approach: This Technique is the next level of the pilot light, reducing recovery time to almost zero. Your application and caching servers are set up and always activated based on your business critical activities but only a minimum sized fleet of EC2 instances are dedicated. The backup system is not capable of handling production load, but can be used for testing, quality assurance and other internal uses. In the event of a disaster, when your on premise data center fails, two things happen. Firstly multiple EC2 instances are dedicated (vertical and horizontal scaling) to bring your application and caching environment up to production load. ELB and Auto Scaling (for distributing traffic) are used to ease scaling up. Secondly using Amazon Route 53 user traffic is rerouted instantly using elastic IP addresses and there is instant recovery of your system with almost zero down time.
4. Multi-Site Approach: Well this is the optimum technique in backup and DR and is the next step after warm standby. All activities in the preparatory stage are similar to a warm standby; except that AWS backup on Cloud is also used to handle some portions of the user traffic using Route 53. When a disaster strikes, the rest of the traffic that was pointing to the on premise servers are rerouted to AWS and using auto scaling techniques multiple EC2 instances are deployed to handle full production capacity. You can further increase the availability of your multi-site solution by designing Multi-AZ architectures.
The diagram below shows exactly how the Pilot Light Approach works, in the occurrence of a disaster :
Solution – Pilot Light Recovery Phase
For a better understanding of Amazon Web Services read white papers on AWS features.
- Backup and Disaster Recovery by Glen Robinson, Ianni Vamvadelis, and Attila Narin
- Building Fault-Tolerant Applications on AWS by Jeff Barr, Attila Narin, and Jinesh Varia
- Cloudtweaks comic by D. Fletcher
- Amazon Web Services
To see more about our Backup and DR solution and other solutions visit our website.