Chapters V-IX dealt with server operating environment and its role in ensuring business continuity mostly in cases of ongoing data processing operations. Having a server down and making it up as soon as possible in order to minimize the costs of downtime was the topic in these chapters. Chapter X deals with technologies for ensuring higher levels of data availability in cases of data loss by having data recovered ASAP. Several backup and recovery technologies are explored with focus being on the traditional backup.
An introduction to data protection technologies from business continuity perspective is given.
In addition to server configurations, server operating systems and ServerWare solutions, the second set of business continuity drivers as defined in Chapter III is presented here as a set of data protection technologies. It represents the second layer of an information infrastructure that can be implemented to enhance continuous computing and business continuity. The whole model based on three layers of business continuity technologies is shown on Figure 1. Layer 2 in this model contains the technologies that are used for data backup and recovery.
The layers of the continuous computing infrastructure
Several information technologies are used in order to store data in data centres in an efficient and effective way and protect it such that business does not suffer if, for any reason, data is lost. Primarily, this set comprises three main groups: data storage, data backup and data recovery technologies.
Just like using several what-if scenarios in financial management (e.g., in Excel or any personal productivity tool), in the area of data (information) management there is a need of building several „what-if“ scenarios such as:
What if we our application server goes down; can we do our business without business critical applications running properly? Can we still keep our business „in business“ if main application server is down, or if data is lost?
What if our messaging server goes down and stay inactive for couple of hours? What is going to happen if an important e-mail went to spam messages that are automatically removed from the messaging server?
What if our Web server goes down and is unreachable for several hours?
What if our CRM server gets into a „blue screen of death“; how long our existing customers and our prospectives will not be able to connect to our server and get necessary data about the products they want to buy?
What if our primary data storage (har disk) crashed? Do we have backup, on which media, how long will it take to recover from that situation?
What if we get a hardware glitch on our RAID system? What is going to happen with our data stored on it?
What if our main data backup medium is broken and there is no way to restore data onto hard disk?
What if we have a problem on our LAN/WAN infrastructure? Network switch, router, modem, and so forth, is broken and we can not reach our data?
What if we have lost our backup tape (or the whole tape library), on-site due to some sort of disaster or off-site during the transport to a remote location?
What if a major hardware glitch occured on our main server and it caused all data is gone. We have backup taken last night, is it enough from data freshness - validity perspective? How long it will take to recover from that situation, recover data and continue with data processing?
What is going to happen if one of our managers lost his or her notebook with business-critical data on it?
What if we have lost all power in our building? What if we have lost main Internet connection and all Web servers are down?
And so forth.
Traditionally, during the period of more than thirty years, data management was treated in terms of primary data storage in the form of disk-based data management for data processing and secondary data storage in the form of tape-based data management system (tape backup). Storing files on hard disks, taking regular tape backups, having data restored (recovered) in case of data-file corruption or data-file loss, was a standard approach used for more than three decades.