Deciding on electronic vaulting
Rick Cook
Electronic vaulting is especially valuable for small businesses and branch offices that do not have IT people on site. With electronic vaulting, backup to a secure site is automatic and the storage professionals at the vaulting company's site handle the details. Even with sites that have their own IT staff, electronic vaulting can make restores faster and more complete by moving set points closer to real time.
The first thing is to know exactly what the vendors are talking about. Electronic vaulting falls in a continuum of backup solutions and like most things in a continuum, the boundaries are fuzzy. Everyone agrees that electronic vaulting involves moving data over a wire to a remote site. Beyond that, it depends on whom you talk to. In some cases the data is written directly to tape. In others it goes first to a disk array and may then be saved to tape or optical disk. Some companies take the data in volumes. Others work in files and folders, which speeds up recovery of individual files. The one thing most companies offering electronic vaulting define it as is taking periodic images of the data to a remote site.
Beyond that, the two main criteria for deciding on electronic vaulting are the available bandwidth and the cost, according to Ray Ganong, CTO and vice-president of operations at E Vault Inc., an electronic vaulting provider. Even though most electronic vaulting services use a delta backup scheme that transmits only data that has changed, electronic vaulting still requires a good deal of bandwidth. E Vault can do simulations either on a spreadsheet or by running its software to find out how long it will take to back up with the customer's bandwidth.
Often an electronic vaulting system will acquire additional bandwidth. Before dismissing getting a bigger pipe as too expensive, it is worth checking the current prices. Bandwidth costs have dropped sharply in the last three years and the current recession is putting even more pressure on prices. Getting more capacity may be cheaper than you think.
Because electronic vaulting is more expensive that conventional tape backup and less expensive, although slower, than data mirroring, a large part of calculating the cost of electronic vaulting for an enterprise is dividing the data by importance of fast recovery and using electronic vaulting only for those kinds of data where the faster recovery is worth the cost. (Using electronic vaulting at a branch office or small business usually means trading additional data volume for backing up everything for the security and convenience electronic vaulting provides.) "Companies need to classify their data by the impact on business," says Jim Morin, vice-president of strategic planning at CNT, an electronic-vaulting service provider. "For class A (most critical) applications, you would use data mirroring to recover data rapidly and close to the point of data generation. Class B data is important but you can't spend the big bucks on everything. Your class C data is stuff you run maybe every two weeks. If you've got to get tapes via truck it's no big deal." Typically classification involves doing detailed calculations of the cost per hour when the different kinds of data are not available.
Rick Cook has been writing about mass storage since the days when the term meant an 80K floppy disk. The computers he learned on used ferrite cores and magnetic drums. For the last twenty years he has been a freelance writer specializing in storage and other computer issues.
