Chris, Don't forget that by default, Java caches IP addresses for DNS lookups. See this link for more information: http://java.sun.com/j2se/1.4.2/docs/guide/net/properties.html and look at both networkaddress.cache.ttl and sun.net.inetaddr.ttl
On Wed, 10 Nov 2004 16:41:06 -0500, Chris Shenton <[EMAIL PROTECTED]> wrote: > I'm a jmeter newbie but looked through the docs, FAQ, and mail > archives. Running jmeter on FreeBSD-4.10 with jdk-1.4.2. > > My target is a set of three app server boxes running Tomcat-4.1. I've > implemented a cluster with Filip Hanik's back-port of the TC5 > clustering code. > > http://cvs.apache.org/%7Efhanik/ > > I'm trying to test this and make sure it works for us on TC4. > > It seems to work fine in simple browser tests. I have a DNS name > "cluster" which has three A records, one for each node's address. > > [EMAIL PROTECTED](347> dnsip cluster.saic.hq.nasa.gov > 198.116.138.39 198.116.138.106 198.116.138.56 > > I point Mozilla at this and login, click around, etc -- it returns to > the same node each time. I disable tomcat on that node. Upon > subsequent clicks, Mozilla goes to one of the other addresses > associated with the cluster's DNS name. So this works fine. > > But when I configure Jmeter with the same DNS name, it appears that it > looks up the name at startup, only saves one of the three addresses, > and never tries the others. When re-running the same test, it never > goes to a different host. If I disable tomcat on the node it's > probing during a run, it continues to try to connect to the dead node > and never goes to another node. It only goes to a different node if I > actually stop then restart jmeter. > > This makes it impossible for jmeter to test DNS round robin based > clusters. (In my final deployment I'll have a HW load balancer, but > don't have one in my development environment.) > > I think Jmeter should be smart enough to cycle through addresses, or > have each thread randomly pick an address from the list DNS provides, > or prefer one and switch to another if the preferred one is > unavailable (TCP Connection Refused is a pretty good sign of that!). --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
