Information Technology Reference
In-Depth Information
EXERCISE 7.5
Creating Snapshots
It is easy to create a snapshot because it is one of the major functions that every hypervisor
must support. To take a snapshot, follow these steps:
1. Just go to the VM menu for your hypervisor and find your way to Snapshot Or
Take Snapshot.
2. A pop-up window or dialog box should appear in which you can enter a name for the
snapshot and input details for the description parameter.
3. To make identification easier and avoid confusion at a later date, you should describe
what the snapshot is about and what it is used for.
In Hyper-V, the snapshots will be given a default name by the system. Once the process
of taking a snapshot has begun, it will take a while to complete, as indicated by a prog-
ress bar. It's not exactly like taking a picture. You can actually continue working on the
virtual machine you are taking a snapshot of, in theory, but in practice the VM becomes
really slow and unresponsive. So it is better to leave it alone until the process has com-
pleted. The files are created in the directory where the files of the virtual machines are
stored. Again, this may differ depending on the hypervisor being used. For VMware
Workstation and other VMware hypervisor products, these files are located in the
directory where the VMDK files for each virtual machine are stored.
Snapshot Manager Snapshots allow you to create separate states with your virtual
machine, creating different branches in which you can move between. This allows the
user to work with snapshots.
Clones Clones are pretty much related to snapshots, but as the name suggests they are
a complete copy of the original virtual machine. You can actually clone a snapshot of a
virtual machine, which is like just simply duplicating the snapshot, and you can even clone
a current state of a virtual machine, which essentially creates a snapshot of that state. To
understand this, you have to know the difference between a linked clone and a full clone.
Linked Clone A linked clone only stores modifications, which means that if something
goes wrong with the virtual machine, such as it being corrupted, the linked clone befalls
the same fate; that is, it gets corrupted as well. But this method also has a huge benefit,
which is the fact that a linked clone requires very minimal disk space, so is very efficient
in this aspect. This is because only modifications are stored in the clone, which also
leads to a very quick process during clone creation.
The linked clone uses the same virtual disks as the parent as well as all of the installed
applications and files that were available to the parent when the snapshot for the clone
was taken. Any changes made to the disk of the parent do not affect the linked clone, and
in turn any changes made on the clone do not affect the parent. However, the clone is still
linked to the parent, so if the parent is taken down, the clone will not work.
 
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