HOB VDI Business ─ A High Performance Solution

The goal of the HOB VDI Business solution is to enable a user to work as well or better with a remote virtual guest from a client machine as with a desktop PC, and still provide all the advantages that running applications in the computer center offers:

• Simple administration
• Hardware consolidation
• Green IT, i.e., reduction of electrical use and air conditioning
• Simpler backup
• Increased security requirements

With HOB VDI Business, as with Windows Terminal Server Computing, the monitor data from the server as well as the keystrokes and mouse movements from the client are exchanged between the local client and the remote system (with HOB VDI Business, this is a virtual desktop).
Microsoft's Remote Desktop Protocol (RDP) is best suited for the transmission of this data. The platform-independent Java RDP client HOBLink JWT is a highly performant implementation of the RDP protocol.

The HOB VDI Business solution’s high performance is provided, on the one hand, by the optimized RDP client, HOBLink JWT, and, on the other hand, by taking care that the RDP data stream is exchanged directly between the client and virtualized desktop, taking no detours.

In VDI solutions not made by HOB, one will find a connection broker. This connection broker is responsible for connecting the client with the correct virtualized guest.
In the HOB VDI solution, the functions of a connection broker are split between those integrated into the client, and those of the HOB VDI Agents running on the virtualized guests.
The HOB VDI Agent is a service that is installed in the Windows XP or Windows Vista of the virtualized guest.
There is another synchronization unit:  with VDI-WSP, it is contained in the HOB WebSecureProxy, in VDI-VS1, it is the load balancing relay nbbrlb01, which runs on the same Linux system as the virtualized guests.
Through the absence of a connection broker one saves on hardware and performance is increased.
If the RDP data first have to go through the connection broker, there will be an additional delay.
This delay increases the so-called round-trip time, noticeable to the user by the slower reaction of the Windows applications.

If the user access is done not remotely but rather locally (Intranet), as is possible with the HOB VDI-VS1 solution, then additional authentication or additional SSL encryption are unnecessary.

The RDP protocol already has encryption in the standard version: this encryption should be sufficient for local operation.

Without SSL one has a higher performance; this is noticeable in the faster response times of the Windows applications.

With HOB VDI-VS1 true load balancing amongst the host servers is carried out. When a user starts a session on a client, he will be assigned a virtual guest on the server with the least load.

Other VDI solutions achieve equal loading of the host servers by, when necessary, transporting a virtual guest from a host server with too much load to another, less loaded host server.
During this process, the user can continue working.
Nonetheless, this solution can be recommended only conditionally:
The transfer of a virtual guest from one host server to another takes several minutes. During this time, both involved host servers are loaded even further by the transport. Especially the users on the highly loaded host server notice this.

With both HOB VDI solutions a reconnect is possible. If a client loses its TCP session, e.g., due to a network interruption, when it logs in again it will be assigned the same virtual guest and can continue working where the session was interrupted.

To achieve a high performance in the VDI solution, of course, the dimensioning of the hardware and configuration of other software components is important.
A VDI solution especially needs a lot of main memory, as multiples of the virtual guests' operating systems have to be stored in the host server's main memory.
It is therefore recommended to deactivate paging or swapping in the host operating system.
If one is running Windows Vista on the virtual guests, then one Gigabyte real main memory per guest should be available.

The HOB VDI Business solution requires few components, is scalable and proven in practical use.

The load balancing in the HOB VDI solution is patented as US patent number: US 6,950,849 B1.
The patent is titled:
Controlling Load-Balanced Access by User Computers to Server Computers in a Computer Network.
The patent was granted on 27 September 2005.

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