Practical Cloud Knowledge: Install, Configure, and Manage - Deploying and Managing a Cloud Infrastructure - page 195

One major drawback is that malicious software and viruses get backed up as well. This
means that if files and application installations from the source have been infected
without your knowledge, the infection gets backed up as well.

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If the source disk has been infected with damaging malware and viruses
right before backup without the knowledge of the administrator, the infected
portions of the disk get backed up as well. That means you have an infected
backup image. Then if your original source gets corrupted and destroyed by
an infection a short while after backup, you can only turn to your infected
backup image and there would be little chance to save the system.

Selecting the Backup Method
It goes without saying that no one method is good for every scenario. But the differences
between the methods should be enough to give you a good idea of which method to use
based on your organization and the types of workflows you are using. For example, if your
organization works on specific files such as 3D and CAD files and multiple employees need
to access and edit the same files, the best backup method would be the selective file backup
because you will not need to back up whole computers, just the important files people are
working on. The scenario could be that a few folders are automatically backed up to the
cloud or to multiple external local drives just to make sure there are multiple copies. The
backup procedure would be quick since only a few files or folders need to be periodically
backed up when there are actual changes. An organization such as this would be considered
small to medium and will not have that many computers to install and reinstall applications
for, so total image backups for fresh installations are not required but may come in handy.
If an organization deals with massive amounts of data that fill up drives easily, then
total image backups are a must. This type of data is often important, so selective backups
do not apply because all of the data needs to backed up. Magnetic tape backup is the most
favored form because of its relative durability and low price point compared to using disk
drive backups. But backup centers that utilize hard disks are also quite common because
of the ease of restoring data.

Virtual Network Interface Card

A virtual network interface card (virtual NIC), like all concepts described with the word
virtual , is an abstract nontangible construct that is created to emulate the functions of a
physical network interface card. Like the real deal, it requires both high sustained through-
put and low latency.
The virtual NIC appears to the guest OS or virtual machine as a full-pledged PCI
Ethernet controller complete with its own unique MAC address because, as you know, the
virtual machine actually believes itself to be a real physical machine. The virtual NIC can
be connected in two ways: it can be either bridged to a real physical network through a real
physical NIC or connected as is to a virtual network created on the host. In both cases, it is