One of the options for virtual desktops in a Horizon View environment is a linked-clone desktop.  A linked-clone is a copy of a virtual machine, in this case a desktop, that shares its virtual disks with a parent virtual machine.  In a Horizon View environment, linked-clones are based on a snapshot of the virtual desktop parent.

Horizon View Composer is the component of a View environment that provides linked-clone functionality.  Although there are many advantages to using linked-clones, such as more efficient use of space and the ability to update all desktops just by updating a parent VM, they are not required.  Because of this, Horizon View Composer is considered an optional component.  If it is not installed, you will not be able to use linked-clone desktop pools.

Composer Hardware Prerequisites

Composer tends to be the component with the most software prerequisites, so it’s going to be the component that I’m going to set up first.  Unlike the Connection and Security Server components, Composer requires its own SQL database that contains information about vCenter and linked-clone desktops and replicas.

Composer can be installed two ways.  Until View 5.1, Composer had to be installed on the same server that hosted vCenter.  Starting with View 5.1, however, a standalone version of Composer was released.  The standalone version supports both the vCenter Server Virtual Appliance and the vCenter Server Windows application.

The system requirements for View Composer are:
Operating System: Windows Server 2008 R2 or Windows Server 2008 R2 SP1
Processors: At least two 1.4 Ghz processors, 4 2.0 GHz processors recommended
Memory: 4 GB, 8GB recommended for deployments of 50 or more View Desktops

Composer also requires the server that it runs on to have static IPs assigned.

Composer Database Prerequisites

As I mentioned above, Horizon View Composer requires a SQL database to store information on replicas and linked-clone desktops.  Composer supports SQL Server 2005 SP4 and later as well as Oracle 10g and 11g with Patch 5.  The database can be installed on the Composer server or on a remote server.

There is a catch to this – if your environment requires that you use Windows Authentication for accessing a SQL Server database, the database instance must be local to the Composer server.  WIndows authentication is not supported if the Composer database is located on a remote SQL Server instance.

Note: For specific information on which databases and service packs are supported, please refer to the VMware Product Interoperability Matrix.

In the next post, I’ll cover configuring the database connection for View Composer.