August 2012


August 2012

How to setup a load balanced Tomcat cluster using the Apache TomcatConnector – AJP

Two weeks ago, I tested a Barracuda Load Balancer Model 340.

I liked it a lot, all features I needed, quick and easy deployment and administration. No competition for a Citrix VPX 1000 or similar, but it would for sure fulfill all my requirements.

Nevertheless I wanted see if it is possible to save some […]

Configure Squid with Dansguardian

Scenario-: 1. Configure squid Server 2. Configure Dan guardian 3. Configure Iptables 4. Configure Proxy server as a router.Our purpose of proxy server is to sharing internet connection for web browsing performance & configures Dan guardian for content and site blocking.A. Allow Internal to all user with restricted web site and content. B. Allow limited […]

Apache server load balancing with Multiple Tomcat Clustering- :

Load Balancing -: Load balancer accept request from external client and forward them to one of the available Backend servers according to a scheduling algorithm. We can use dedicated hardware and any load balancing software for load balancing Mod_proxy_balancer- : Apache web server’s module of mod_proxy_balancer the apache module developed to provide to load balancing […]

RHCS(Red Hat Cluster Suite) quorum disk

Methods to deal with split-brain situation: 1. Redundant heartbeat path network port communication plus serial port communication 2. I/O fencing Remaining nodes separate failed node from its storage either by shutdown/reboot power port or storage port 3. Quorum disk Quorum disk is a kind of I/O fencing, but the reboot action is executed by failed […]

GFS (Global File System) quickstart

What is GFS? GFS allow all nodes to have direct CONCURRENT write access to the same shared BLOCK storage. For local file system e.g ext3, A shared BLOCK storage can be mounted in multiple nodes, but CONCURRENT write access is not allowed For NFS, the CONCURRENT write access is allowed, but it is not direct […]

Find process causing high iowait Disk Space issues

Disk Space issues

mpstat -P ALL

cat /proc/interrupts

iostat -kd 1iostat -c -tiostat -c -t 2 10 iostat -c 3 iostat -d 5iostat -x 1

sar -b

vmstat -S M 2 5

Find process causing high iowait

netstat -autpn | grep :80netstat -autpn | grep :3306netstat -nanetstat -an|grep :80|sort|morenetstat -an|grep ESTABLISHEDnetstat -ntu | awk ‘{print […]

Jboss clustering config http services

16.5. HTTP ServicesHTTP session replication is used to replicate the state associated with your web clients on other nodes of a cluster. Thus, in the event one of your node crashes, another node in the cluster will be able to recover. Two distinct functions must be performed:

Session state replication

Load-balance of incoming invocations

State […]

Tomcat clustering and failover

In this post I will describe how to implement a functional Tomcat cluster with load balancing and failover

I did a great deal of research trying to get this environment working. There are a number of good tutorials for simple Tomcat clustering and load balancing. I was unable to find an example that was […]

Implement a Dynamic Tomcat Cluster with Mod_Cluster

Apache Tomcat, the open source Web application server, hosts an estimated 70 percent of small Java Web applications. However Tomcat can become overburdened when faced with spikes in user requests. One way to ensure that your Tomcat servers are utilized to their maximum capacity is to connect and cluster them in a single environment and […]

Crazy way to do JBOSS and Tomcat Loadbalancing :)

Crazy way to do JBOSS and Tomcat Loadbalancing

Mod clusteris an http based load balancer which greatly simplify the setup of an http cluster. It ships as a set of modules which need to be installed on the httpd server and a Service Archive Library (.sar) which needs to be deployed on JBoss AS (It […]