load balancing

A Tale of Two Load Balancers

It was the best of load balancers, it was the worst of load balancers, it was the age of happy users, it was the age of frustrated users. I get to see a variety of interesting network problems; sometimes these are first-hand, but more frequently now these are through our partner organization. Some are old hat; TCP window constraints on high latency networks remain at the top of that list. … read more

Sync your Timeouts: When Load Balancers Cause Database Deadlocks

Have you seen this error message before “java.sql.Exception: ORA-00060: deadlock detected while waiting for resource”? This is caused when parallel updates require locks on either rows or tables in your database. I recently ran into this exception on an instance of an IBM eCommerce Server. The first thought was that there are simply too many people hitting the same functionality that updates Sales Tax Summary information – which was showing … read more

Filling Citrix Visibility Gap with Application-Aware Network Performance Monitoring – Part 1: Load Balancing

There are many reasons why companies choose Citrix XenApp or XenDesktop. Citrix can lower the costs of desktop management and simplify access to hosted applications from any device. Citrix seems like an ideal solution but it introduces certain challenges to application performance monitoring (APM). With Citrix we get yet another component in the data center to take care of. In addition, the virtualized application delivery becomes “black boxed” from the APM perspective. It gets harder to isolate the fault domain to either the network, infrastructure or applications themselves. In this two-part series we will analyze how to discover and handle some performance issues which can happen in the Citrix enabled environment. We start by looking at how to monitor network performance to discover potential problems with load balancing. In the second part we will look into managing experience of Citrix users from the perspective of network monitoring. … read more

Balancing the Load

A question that every online application provider will face eventually is: does my application scale? Can I add an extra 100 users and still ensure the same user experience? If the application architecture is properly designed the easiest way is to put additional server behind load balancer to handle more traffic. In this article we recount an incident that happened to one of our clients when the cause of a … read more