The Many States of Disaster Recovery

15 Feb

Throughout my tenure with IBM and EMC, I have worked with many customers that are looking for some sort of business continuity plan to help them weather a true disaster.  What I have found, is that this idea of BC or “Disaster Recovery” can mean different things to different companies and the decisions they make are determined mostly by money and need.  What it boils down to is the simple question: “How long can I afford to be down, and how much data can I afford to lose?”

I’d like to take you through the three most popular designs and why customers are choosing these types of business continuity plans. 


First, Disaster Recovery is the ability to return to business in the event of total data loss at a primary location (Site A).  For a lot of companies in the SMB space, this doesn’t mean immediate recovery.  For these customers, they can and do have the ability to lose a day’s worth of data and can be down for a week or longer as they rebuild their IT.  For these customers, simply getting your data offsite through backups will accomplish this task and it is the least expensive option for true DR.


Data Loss: Any new data since last backup until time of disaster

Recovery Time: 1 week or more, depends on how long it takes to purchase and re-build your data center

Cost:  Least expensive


In this second scenario the business is still going to lose any data that was not backed up before the disaster hit but they now have a faster recovery time.  This set up is great for businesses that have the ability to lose data, but not significant downtime on their mission critical applications.   

Data Loss: Any new data since last backup until time of disaster

Recovery Time:  A few hours on your mission critical data as you recover to your offsite servers

Cost:  Moderate.  Have to pay for hosting and the additional servers and networking.



In my experience, the previous two scenarios are good enough for most SMB customers, but there are those companies out there that are either unable to lose any data and need true synchronous replication or are unable to weather any downtime to their business.  For these customers, SAN level replication is a true requirement.


Data Loss: Any data not replicated, can be a few seconds to a few minutes depending on bandwidth and data change rate.

Recovery Time:  Immediate.

Cost: Highest.  Customers in this scenario will have two fully functional IT data centers.  This cost can be minimized by running in an Active/Active configuration.


With the many different options out there for business continuity, it is important for businesses to truly understand the business implications of a true disaster and what their individual company can afford to lose.  Too many times companies are choosing the most expensive option (SAN level replication) because that is what their peers or IT professionals are telling them is best, and not taking a serious look at what their business needs are.  Understanding these needs will help your company in designing a business continuity plan that is right for your needs.

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Posted by on February 15, 2013 in Storage


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