White Papers

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CREATING SMART CLONES
Creating clones in any environment can be very useful for a number of reasons.
They allow you to quickly deploy multiple sets of virtual machines to either test
configurations or create identical environments to use. VSM has the capability
to not only clone running virtual machine environments but also create clones
from previous Smart Copies. This allows the administrator to bring online
copies of virtual machines from a prior point in time. This can be helpful for
troubleshooting or side by side comparison of machines.
Another great use of Smart Copy Clones is the ability to test new software
without impact to existing production machines. Typically an administrator
might take a Smart Copy of a set of virtual machines and then upgrade the
software. If this results in an outage or the software is incompatible, the
administrator can roll back to a previous known good Smart Copy. However
this can be disruptive as the environment will be unavailable during the restore.
Creating brand new machines to test the software upgrade very rarely
introduces the same issues that might come up with existing software builds.
Another option an administrator can do is to bring online a clone of the virtual
environment, isolate it from the production environment, and then run the
upgrades and testing on the cloned environment. This way should anything
negative occur, at no point is the production environment impacted.
Clones can also be used when creating identical environments for testing and
development environments, and when combined with the PS Series thin clone
feature, can result in significant space savings. By taking a clone of several
virtual machines residing on a datastore volume, the volume can be converted
into a thin clone template and several space efficient copies of these VMs can
be spun off and given to various developers. For more information on
leveraging thin clones in your environment refer to technical report TR1063
Dell EqualLogic PS Series Template Volumes and Thin Clones: How and When
to Use them .
It is very important to note that no matter what the reason is for utilizing
clones, they are an exact match of the existing virtual machine. This means the
hostname, the IP address, and the application namespace is identical. It is
therefore vital that whenever a cloned virtual environment is brought online it
is segmented from the production environment to avoid any conflict. This can
be done with isolated virtual switches, networking changes or other methods.
NOTE: Virtual Machines which have drives spanning multiple datastore
volumes are supported by Smart Copies. However during a clone operation
these virtual machines will have the additional drive registration still pointing to
the original volumes. This will cause conflicts without some manual
configuration steps. It is recommended that any VMs that are desired to be
cloned have all of their data residing on a single datastore volume to avoid any
potential issues.