If you're concerned only with backing up your servers, then you probably have SCSI devices, and you know about...
backup performance on SCSI. But you should be concerned with backing up desktops. If you aren't, who will be? So that means you may have to concern yourself with using IDE devices for backups. That's because IDE (or ATAPI) is the most popular peripheral interface on desktop and other small systems because it is inexpensive and flexible. Everything from hard drives to CD-ROMs to backup tape drives can be attached to the IDE interface for reasonable performance at a low cost.
However the performance isn't always so reasonable. If you configure an IDE-based system running Windows 2000 incorrectly, backup times can become extremely long and verification may produce errors reflecting a Plug and Play problem such as 'unsafe removal of device.' This can be especially puzzling if the system was upgraded to Windows 2000 without changing the hardware configuration.
What is happening is that Windows 2000's autorun feature for the CD-ROM drive is interfering with the operation of the tape drive. The operating system polls the CD-ROM drive every second looking for media changes and that prevents the tape drive from transferring data at a high rate. This also interferes with the verification operation.
The solution (aside from going to a SCSI interface) is to disable the autorun feature (explained in Microsoft Knowledge Base article 155217) or putting the tape and CD-ROM on separate IDE controllers.
Microsoft discusses the problem in Knowledge Base article 263480 "Backup Runs Very Slow on IDE-Based Tape Drives and Verification Operations May Not Work."
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.