RAIDing Windows XP:
How to Install Windows XP
on a RAID Array of Hard Disk Drives
by Larry F. Byard
Last updated: 1/18/2004
INTRODUCTION. This article will show you step-by-step how to set up simple RAID configurations of hard disk drives and how to install Windows XP on them.
WHAT IS RAID?
A RAID, or Redundant Array of Inexpensive Disks, is a collection of disk drives that collectively act as a single storage system. In other words, two or more hard disk drives which are grouped together and appear as a single disk drive. Or, in practice, it can also be two or more disk partitions grouped together and appear as a single partition/logical drive. A partition or volume is just that, a demarcated and contiguous section of a drive which appears like a drive--a logical drive. There are six levels of RAID and the features of more than one level can combined in a RAID. The Highpoint HPT37x series of RAID controllers discussed in this article supports three common flavors of RAID used in PCs:
Stripping (RAID Level 0). Provides performance (not redundant as implied in the acronym). Data is evenly spread over identical drives. That is, parts of file can be spread over more than one drive. Data can be read and written in parallel. Performance is very good. Failure of any one disk in the array results in data loss. This kind of RAID would be good for storing large files of temporary nature, but you sure wouldn't want to put you accounting package on one.
Mirroring (RAID level 1). Provides redundancy. Two drives duplicate each other identically. If one drive fails, all of the data is available on the other one. The read performance of mirrored drives can be increased through load balancing and elevator sorting (I won't go into elevator sorting here). Simply put, when data is requested it is read from the least busy drive. Put that accounting package on this one; I did. But remember it is possible for Windows to "scribble" on a hard disk. In this arrangement, a scribble on one drive is more than likely a "scribble" on both drives--mirrored garbage is garbage.
- Striping/Mirroring (RAID 0+1 or 0/1). Provides performance and redundancy. Two sets of stripped drives (four drives in the case of the HP37x controllers) are mirrored. This arrangement may be fast and redundant, but it is also expensive and complicated.
- JBOD (Just a Bunch Of Disks). Is not really a RAID in the sense that it provides the data protection and/or higher performance. But, rather, it simply combines multiple drives into a single volume with larger capacity that can span the drives. The multiple drives look like one drive to the operating system.
This article covers the installation of the first two RAID configurations and leaves the other two as an exercise for the reader.
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