Multiple Disk Volumes

In many critical servers, multiple disks are used for performance, reliability, or scalability. The disks are merged and processed so that they look normal but they are not. This chapter covers RAID and disk spanning systems, both of which can be difficult to investigate. There can be many challenges when investigating a system that uses a multiple disk volume, and not all the problems have been solved. This chapter explains the technology behind both of these volume systems and then provides some suggestions for analyzing or acquiring the data. Of any chapter in this book, this will likely become outdated the most quickly because new technology is being developed to create new types of storage systems and because new analysis techniques will be developed to help fill the void in this area. The first part of this chapter examines RAID systems, which provide redundancy, and the second part of the chapter examines disk spanning, which creates larger volumes.