Guidelines for Slow Server

Hypothesis

Users complain about having to try several times to connect to a web-based application named “Salesforce”. The administrator suspects the application server hosting “Salesforce” is slow.

How to analyze the problem

First, check to see if all applications on the application server hosting “Salesforce” are slow or if it is just that particular application. If all applications are slow, then the application server may, in fact, be a slow server. If just the one web-based application “Salesforce” is slow, while the other applications (CRM) are responding quickly, the problem may be the application.

To begin diagnosis, go to “Monitoring” -> “Clt/Srv Table”. Select the application server from the drop-down box labeled “Server Zone” and click “Search”.

• If we see that all applications on the server are responding slowly, i.e., the SRT values are high for both “Salesforce” and “CRM”, the issue is related to the server, not to applications.
• Second, check the Connection Time of the application server. If the connection times are high, then this may also indicate a slow server.
• Third, check for retransmissions between the clients and the application server. If there are a lot of retransmissions, then either the application server or a network device in between are dropping packets. Go to “Monitoring” -> “Performance Over Time chart”. Select the application server “Salesforce” from the drop-down box labeled “Server Zone” and click “Search”.

Here, we see that there is a high Retransmission Rate (RR Server) going from the clients to the application server. However, none of the packets from the server to the clients needed to be retransmitted (RR Client is around 0). This indicates that the application server is, in fact, dropping the packets and is therefore a slow server (assuming that the route taken from the client to the server is the same route taken from the server to the client as is industry standard practice).

Lastly, check the TCP errors of the clients and the Application server. If the server reset count or number of timeouted sessions is high, this is a further indication of a slow server. Go to Analysis -> TCP errors. Select the application server “Salesforce” from the drop-down box labeled “Server Zone” and click Search.

Here, we see that there are a lot of server resets and timeouts. Given all the above information, we can conclude that the application server is operating slowly. At this point, the server administrator should perform direct diagnosis on the application server to verify CPU, RAM and HD usage.