MCSA/MCSE Self-Paced Training Kit (Exam 70-270): Installing ...

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Lesson 1 Managing and Troubleshooting Disks and Volumes
Windows XP supports the following types of dynamic volumes
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Simple volume A simple volume can contain disk space from a single disk and can
be extended if necessary.
Spanned volume A spanned volume can contain disk space from 2 or more (up to
a maximum of 32) disks. The amount of disk space from each disk can vary. You
will most often use spanned volumes when a simple volume is running low on
disk space and you need to extend the volume by using space on another hard
disk. You can continue to extend spanned volumes to include areas from additional
hard disks as necessary. When Windows writes data to a spanned volume,
it writes data to the area on the first disk until the area is filled, and then writes
data to the area on the second disk, and so on. There is no fault tolerance in
spanned volumes. If any of the disks containing the spanned volume fail, you lose
all data in the entire spanned volume.
Striped volume A striped volume can contain disk space from 2 or more (up to a
maximum of 32) disks. Unlike spanned volumes, striped volumes require that you
use an identical amount of disk space from each disk. When Windows writes data
to a striped volume, it divides the data into 64 KB chunks and writes to the disks
in a fixed order. Thus, Windows will split a 128 KB file into two 64 KB chunks,
and then stores each chunk on a separate disk. Striped volumes provide increased
performance because it is faster to read or write two smaller pieces of a file on two
drives than to read or write the entire file on a single drive. However, you cannot
extend striped volumes, and they provide no fault tolerance. If any of the disks
that contain the striped volume fail, you lose all data on the volume. Striped volumes
are also referred to as RAID-0.
Exam Tip Windows XP Professional does not support fault-tolerant disk configurations.
Spanned volumes simply allow you to use different amounts of disk space from multiple hard
disks in a single volume. Striped volumes allow you use an identical amount of disk space
from multiple hard disks. The advantage of using striped volumes is that Windows can write
information to the disk more quickly.