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7 PS Series Template Volumes and Thin Clones: How and When to Use Them | TR1063
3 Use cases for template volumes and thin clones
PS Series thin clones can be used in a number of ways, ranging from gold image deployments to object
distribution. The simplest use for thin clones is to distribute like volume data to many locations or business
units by creating copies from a template. This allows each location or business unit to use the data without
multiplying out the space requirements.
Some other more advanced uses for thin clones are discussed in this section as well as possible use cases
and how to configure them using template volumes and thin clones.
3.1 Hyper-V virtual machine deployment using thin clones
One common use case for template volumes and thin clones is rapid OS deployment. In a virtual
environment, thin clones can be used for virtual machine distribution based off boot images. This is possible
in Hyper-V environments by using the import/export operations in conjunction with template volumes and thin
clones. Using the following steps, it is very easy to distribute VMs based on a single or multiple gold VM
images.
1. Create two PS Series volumes and add them to the Hyper-V host.
2. Create a VM and build the gold image on one of the volumes.
3. Once the image is in the desired state, power down the VM and export it to the second volume.
4. Use Disk Manager to set the second volume offline in the host. Optionally, log off the volume from the
iSCSI initiator (logging off will make sure not to confuse the template with the thin clone copies).
5. Make the second volume a template volume in the Group Manager. This will make it read-only and
serve as the gold master image for the VM deployment. It is recommended to remove the access
control on the template volume so that it does not show up in the host initiator.
6. Create thin clones from the template and give each thin clone access control to the Hyper-V host.
7. Refresh the iSCSI initiator in the Hyper-V host and log into the thin clone.
8. Use Disk Manager to give the newly attached thin clone a drive letter.
9. Using Hyper-V manager, import the VM on the thin clone to the Hyper-V host.
10. Repeat steps 6–9 for as many VM copies as needed.
Note: These procedures can be included for use with VHDs hosting multiple VMs as well as CSVs in a
Hyper-V cluster although the operations required in these environments are more difficult to manage and
maintain and not ideal for thin clone use cases.
3.2 SQL Server database distribution using template databases
In a SQL Server world, template volumes and thin clones can be useful to quickly distribute large numbers of
database copies to test and development teams without consuming valuable storage space. Thin clones
utilize the read-only data of the template volume and new writes get written to thin clone space. In a test and
development environment, this would mean any new builds or tests on a thin clone database will take up very
minimal storage space and if a build does not work or breaks, the database can be easily reverted back to the
state of the template database.