Excessive Servant Region Startup Time
 Technote (troubleshooting)
 
Problem(Abstract)
WebSphere® Application Server for z/OS® server startup time is two or three times longer than normal, and throughput is reduced to a fraction of what is typical. CPU consumption is not excessive, but every request seems to take longer than normal.
 
Cause
Unresponsive or nonexistent domain name servers in DNS configuration greatly increases response time for the server.

The default value for TCPIP's RESOLVERTIMEOUT requests is 30 seconds. TCPIP uses a preconfigured set of Domain Name Servers each time an IP hostname or IP hostaddr lookup occurs. If the first server listed in the set is not available, TCPIP will wait for 30 seconds before attempting to use the second server in the list. Each subsequent non-operational DNS server listed will add 30 more seconds to the lookup response time. There can be several lookups per request in the server, and this can add several minutes to the response time for each request.

 
Resolving the problem
Eliminate the non-operational DNS servers from the configuration.
 
 
 


Document Information


Current web document: swg21197873.html
Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server for z/OS > Hangs/Performance Degradation
Operating system(s): z/OS
Software version: 5.1
Software edition:
Reference #: 1197873
IBM Group: Software Group
Modified date: Feb 9, 2005