| 1 | <?xml version="1.0" encoding="UTF-8"?>
|
|---|
| 2 | <!DOCTYPE topic
|
|---|
| 3 | PUBLIC "-//OASIS//DTD DITA Topic//EN" "topic.dtd">
|
|---|
| 4 | <topic xml:lang="en-us" id="virt-why-useful">
|
|---|
| 5 | <title>Why is Virtualization Useful?</title>
|
|---|
| 6 |
|
|---|
| 7 | <body>
|
|---|
| 8 | <p>The techniques and features that <ph conkeyref="vbox-conkeyref-phrases/product-name"/> provides are
|
|---|
| 9 | useful in the following scenarios: </p>
|
|---|
| 10 | <ul>
|
|---|
| 11 | <li>
|
|---|
| 12 | <p><b outputclass="bold">Running multiple operating systems simultaneously.</b>
|
|---|
| 13 | <ph conkeyref="vbox-conkeyref-phrases/product-name"/> enables you to run more than one OS at a time. This way,
|
|---|
| 14 | you can run software written for one OS on another, such as Windows software on Linux or a Mac, without having
|
|---|
| 15 | to reboot to use it. Since you can configure what kinds of <i>virtual</i> hardware should be presented to each
|
|---|
| 16 | such OS, you can install an old OS such as DOS or OS/2 even if your real computer's hardware is no longer
|
|---|
| 17 | supported by that OS. </p>
|
|---|
| 18 | </li>
|
|---|
| 19 | <li>
|
|---|
| 20 | <p><b outputclass="bold">Easier software installations.</b> Software vendors can use virtual
|
|---|
| 21 | machines to ship entire software configurations. For example, installing a complete mail server solution on a
|
|---|
| 22 | real machine can be a tedious task. With <ph conkeyref="vbox-conkeyref-phrases/product-name"/>, such a complex
|
|---|
| 23 | setup, often called an <i>appliance</i>, can be packed into a virtual machine. Installing and running a mail
|
|---|
| 24 | server becomes as easy as importing such an appliance into <ph conkeyref="vbox-conkeyref-phrases/product-name"
|
|---|
| 25 | />. </p>
|
|---|
| 26 | </li>
|
|---|
| 27 | <li>
|
|---|
| 28 | <p><b outputclass="bold">Testing and disaster recovery.</b> Once installed, a virtual machine and
|
|---|
| 29 | its virtual hard disks can be considered a <i>container</i> that can be arbitrarily frozen, woken up, copied,
|
|---|
| 30 | backed up, and transported between hosts. </p>
|
|---|
| 31 | <p>Using virtual machines enables you to build and test a multinode networked
|
|---|
| 32 | service, for example. Issues with networking, operating system, and software configuration
|
|---|
| 33 | can be investigated easily. </p>
|
|---|
| 34 | <p>In addition to that, with the use of another <ph conkeyref="vbox-conkeyref-phrases/product-name"
|
|---|
| 35 | /> feature called <i>snapshots</i>, one can save a particular state of a virtual machine and revert back to
|
|---|
| 36 | that state, if necessary. This way, one can freely experiment with a computing environment. If something goes
|
|---|
| 37 | wrong, such as problems after installing software or infecting the guest with a virus, you can easily switch
|
|---|
| 38 | back to a previous snapshot and avoid the need of frequent backups and restores. </p>
|
|---|
| 39 | <p>Any number of snapshots can be created, allowing you to travel back and forward in virtual
|
|---|
| 40 | machine time. You can delete snapshots while a VM is running to reclaim disk space. </p>
|
|---|
| 41 | </li>
|
|---|
| 42 | <li>
|
|---|
| 43 | <p><b outputclass="bold">Infrastructure consolidation.</b> Virtualization can significantly reduce
|
|---|
| 44 | hardware and electricity costs. Most of the time, computers today only use a fraction of their potential power
|
|---|
| 45 | and run with low average system loads. A lot of hardware resources as well as electricity is thereby wasted.
|
|---|
| 46 | So, instead of running many such physical computers that are only partially used, one can pack many virtual
|
|---|
| 47 | machines onto a few powerful hosts and balance the loads between them. </p>
|
|---|
| 48 | </li>
|
|---|
| 49 | </ul>
|
|---|
| 50 | </body>
|
|---|
| 51 |
|
|---|
| 52 | </topic>
|
|---|
