Database Reference
In-Depth Information
Load balancing issues
The load balancing solution you designed for your SOA Suite composite application
must go through the functional validation for load sharing, failover, and failback.
A few facts before we worry about analyzing the load sharing issues. In the case of
Active-Active load sharing between multiple sites, it is usually done through L7 load
balancers; we are load balancing the users not the payload these users will bring to
the application server(s). Ensure that the health checks are configured by the applic-
ation server process. One should not share the service endpoints serviced by the dif-
ferent processes at the application server. We must validate if the health checks are
working as we thought.
Insomecases,youmayfindthattheL7loadbalancerisnotabletoperformthehealth
checks implemented for a service endpoint. Ensure that there is a network route for
the service endpoints' IP addresses and port from the L7 load balancer appliances.
If you notice that the server load sharing is not sending a fair share between servers,
ensure that the least connection load sharing algorithm is used and L7 health checks
are implemented for the application server health. In some cases, you may find the L4
load balancer is not able to perform the health checks implemented for a service en-
dpoint running at the web/application server. Ensure that there is a network route for
the service endpoints' IP addresses and port from the L4 load balancer appliances.
If a server or site is getting its share of users plus/minus 20 percent of the design time
share, then load sharing is working fine. It is almost impossible to get the exact load
sharing. For example, if there are three server(s) you may find these servers will get
anywhere between 27 to 39 percent of the total users and if there are two server(s)
you may find these servers will get anywhere between 40 to 60 percent of the total
users.
