Barracuda Networks Load Balancer, Administrator'S Manual

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12 Barracuda Load Balancer Administrator’s Guide
Cookie persistence is not available if using the Direct Server Return (DSR) mode of deployment
unless the application manages the cookies. This is because the cookie is inserted into the data stream
by the Barracuda Load Balancer when the traffic is outbound. In DSR the traffic goes directly to the
client, bypassing the Barracuda Load Balancer, so there is no opportunity to insert a cookie.
Session Directory Integration
Session persistence may also be maintained by querying Windows Server 2003 Session Directory or
Windows Server 2008 Terminal Services Session Broker. The Barracuda Load Balancer notes the
open sessions on each Terminal Server and checks if each connecting client already has a session open
on a particular Terminal Server. If the client has an open session, the Barracuda Load Balancer
forwards that user to the appropriate Terminal Server.
SSL Offloading / Acceleration
The Barracuda Load Balancer has the ability to handle SSL encryption and decryption locally, to help
ease the burden on backend Real Servers. Hardware SSL Acceleration is available on selected
models.
SSL offloading is not available if using the Direct Server Return mode of deployment.
Scheduling Policy
The Barracuda Load Balancer supports multiple scheduling technologies that support server
weighting including Weighted Least Connection (WLC) and Weighted Round Robin (WRR). The
Barracuda Load Balancer also supports
adaptive scheduling , a resource based algorithm that can
take into account factors like CPU load or a customer modifiable load URL option. You can also
specify that certain servers handle more traffic than others.
Automated Service Monitor
Barracuda Load Balancer features a fully integrated Service Monitor which can be configured to re-
route traffic based on automated tests of servers being clustered or their upstream and downstream
dependent infrastructure components. Downed servers are automatically removed from the farm
within seconds of server failure.
Multiple Deployment Modes
The Barracuda Load Balancers support Route-Path, Bridge-Path, and Direct Server Return modes, for
the most flexibility of any load balancer on the market. Route-Path offers increased flexibility, while
Bridge-Path allows deployment without changes to existing IP infrastructure. Direct Server Return
allows for maximum throughput, ideal for content delivery networks.