CHAPTER 4: Advanced Hardware Setup40How it makes file storage cheaperBecause RAID 0 lets your computer see multiple hard drives asa single drive, you can install several lower capacity (lessexpensive) drives and have the same single-drive storagesimplicity and capacity as a larger, more expensive hard drive.DrawbacksUnfortunately, RAID 0 lets multiple drives behave as one inanother way. If part of the array fails (such as a hard drivecrashing), the entire array fails. Because the drives are treatedlike a single drive, parts of files (including operating systemfiles) can be spread across several drives, leaving the computerwith only file fragments if one drive fails. Regular and frequentbackups are critical.Another drawback is that RAID 0 treats each hard drive as if ithas the storage capacity of the smallest drive in the array. Soif you have three drives (300 GB, 250 GB, and 200 GB) in aRAID 0 array, your computer only recognizes 600 GB totalcapacity.RAID 1 for securityRAID 1 maintains a complete copy of all files on each physicalhard drive in the array. Maintaining simultaneous, completecopies of files across multiple hard drives is called mirroring.If a drive fails, the mirrored drive takes over and acts as theprimary drive.In the following graphic, each letter represents a unique blockof data, and each column represents a separate hard drive.File reading performance (seek time) is increased using thesame methods that RAID 0 uses, although writing speed is thesame as if writing to a single hard drive.ABCABCRAID 1