But before investing in a DR site and buying equipment, a company must ask itself two questions: What data is so vital that, if it were lost, the company would go out of business? How much time can the company afford to lose if the local site went down?
Only then can hardware and software components be purchased and a DRP implemented.
This tech roundup discusses how DR tools are used, their evolution and what the competitive landscape looks like.
The main aspect of a DRP -- sometimes referred to as a business continuity plan (BCP) -- is the off-site replication of data. There are a number of replication tools, and they're growing more common as the cost of disk and bandwidth decrease.
With synchronous replication, data from site A is backed up simultaneously and continuously at site B. While ideal, synchronous replication is often too expensive for most except the largest companies.
Asynchronous replication, in which data from site A is backed up at site B, but not immediately, is available at significantly lower costs and has made DR more accessible to more businesses.
According to Arun Taneja, consulting analyst and founder of the Taneja Group in Hopkinton, Mass., a company must know its recovery point objective (RPO) and recovery time objective (RTO) before it can know what kind of replication it should be using.
"If you only think about equipment, you will just be spending lots of money and still be naked, so to speak," Taneja says. "You first need to know what data is mission-critical and how long your main data center can afford to be down."
Key vendors and products
There are three types of off-site DR replication products: array-based, third-party and managed services.
Array-based replication employs software that allows users to replicate between two proprietary storage arrays. An example of this is SRDF offered by EMC Corp., which replicates between two EMC Symmetrix systems. Other products in this area include IBM Corp.'s Peer to Peer Remote Copy (PPRC), between IBM arrays, and Hitachi Data Systems' (HDS) TrueCopy, between two HDS arrays.
Third-party products, which replicate data from a site A heterogeneous environment to site B, include FalconStor Software's IPStor replication software, NSI Software's DoubleTake and GeoCluster, Topio Inc.'s Data Protection Suite, SANRAD's Global Disaster Recovery (GDR), and Kashya Inc.'s Data Protection Appliance, which is distributed by Unisys and Xiotech.
Managed services are newest in this arena and are gaining popularity with mid-sized companies. With managed services, an outsourcer operates a company's remote site or the whole DR operation.
Among companies offering such services are: WilTel Communications, with a SONET network with space for rent; StorageTek, with services through Arsenal Digital Solutions Inc.; Evault; IBM Global Services; and Hewlett-Packard Co. (HP), which has at times taken over entire data centers for DR purposes.
Trends and innovations
Tony Asaro, senior analyst at Enterprise Strategy Group in Milford, Mass., says that one widely used method of data replication is installing host-based software applications on individual servers and then replicating all the data to a remote server running the same software.
However, Asaro says most companies are still doing DR the old-fashioned way: sending tapes off-site. "Naturally, this is not the most efficient method, but it does provide a low-cost solution," Asaro says.
Yankee Group senior analyst Stephanie Balaouras agrees that despite technical innovations, users have been slow to implement a sophisticated DR plan.
A survey conducted by Balaouras last year showed that a high number of users still do not deploy DR strategies to the extent that they could. "The highest was financial services with 54%," she says. "I was kind of expecting a little bit higher at this stage of the game."
According to Balaouras' study, the higher the company revenue, the more likely they were to have long-distance DR replication products in use. "I think it's totally been a cost issue," she concludes.
Balaouras adds that the availability of modular, affordable mid-tier storage, the dropping cost of bandwidth and a wider variety of options for network transport is raising both awareness and use of DR replication technologies.
Going forward, Asaro predicts that innovations such as data de-duplication, data compression and encryption will help increase DR plans. "Through de-duplication, companies can only send unique data over the WAN, thereby minimizing bandwidth requirements and network costs," Asaro says.
Asaro highlighted Asigra Inc., Avamar Technologies, Inc. and Data Domain as vendors providing de-duplication and data compression.
This was first published in August 2005