When it comes to backing up applications outside the data center, there are multiple strategies. Do you back up to a single, central server? Does each box have its
own backup repository? Do you back up all machines the same, or are there special procedures for critical servers?
We've all heard the disk-to-disk backup "strategy" that goes: "We copied all the documents in the Contracts folder over to a folder named Backup on our server." Even more sophisticated shops that have tape systems in place make the fatal mistake of failing to verify that the backups worked. Trusting the system because you don't have time to do spot checks is risky business.
It doesn't have to be this way. Storage system prices have been dropping. New options and deals are plentiful. For example, Microsoft's introduction in May of Windows Storage Server gave vendors a low-cost base platform, spurring customization. Windows Storage Server consolidates storage functionality in a Windows platform at a reasonable price to OEMs. Meanwhile, S-ATA (Serial ATA) has reduced the per-gigabyte cost of hard drives--S-ATA drives are now considerably less expensive than their SCSI counterparts. All this lets vendors build inexpensive storage machines on a common platform.
The result is that many affordable backup options are available for small and midsize businesses as well as enterprise-level departments. D2D2T (disk-to-disk-to-tape) appliances let backups run to disk and then, over time, stream data off to tape, enabling your core systems to back up using fast disk-to-disk techniques, and off-loading the slower disk-to-tape backups to the appliances. Depending on the technology and vendor you use, disk-to-disk backups can be two to five times faster than disk-to-tape backups. More important, restores in those first few hours between backup and when the data is streamed to tape occur at random-seek disk speeds instead of streaming tape speeds.