Googlielmo's blog

Apache JMeter ( http://jmeter.apache.org/ ) added support for MongoDB since its 2.10 release. In this post I am referring to the latest JMeter release (2.13). A preliminary JMeter setup is needed before starting your first test plan for MongoDB. It uses Groovy as scripting reference language, so Groovy needs to be set up for our favorite load testing tool. Follow these steps to complete the set up: Download Groovy from the official website ( http://www.groovy-lang.org/download.html ). In this post I am referring to the Groovy release 2.4.4, but using later versions is fine. Copy the groovy-all-2.4.4.jar to the $JMETER_HOME/lib folder. Restart JMeter if it was running while adding the Groovy JAR file. Now you can start creating a test plan for MongoDB load testing. From the UI select the MongoDB template ( File -> Templates... ). The new test plan has a MongoDB Source Config element. Here you have to setup the connection details for the database to be tested: The Threa

Whether you should fail to start a mongod service on Linux and see in the database logs an error message like the following: Failed to unlink socket file /tmp/mongodb-27017.sock errno:1 Operation not permitted Its root cause is a permission issue: the previous restart/stop as root user didn't complete properly, so the temporary .sock file couldn't be deleted. Delete the file manually as root before restarting the service and the sun will shine again.

During an Hadoop cluster installation on Red Hat/CentOS using Apache Ambari ( https://ambari.apache.org/ ), a DataNode could fail to install with the following error: resource_management.core.exceptions.Fail: Execution of '/usr/bin/yum -d 0 -e 0 -y install snappy-devel' returned 1. Error: Package: snappy-devel-1.0.5-1.el6.x86_64 (HDP-UTILS-1.1.0.20)            Requires: snappy(x86-64) = 1.0.5-1.el6            Installed: snappy-1.1.0-1.el6.x86_64 (@ftp3-updates)                snappy(x86-64) = 1.1.0-1.el6            Available: snappy-1.0.5-1.el6.x86_64 (HDP-UTILS-1.1.0.20)                snappy(x86-64) = 1.0.5-1.el6  You could try using --skip-broken to work around the problem  You could try running: rpm -Va --nofiles --nodigest The root cause here is the following: Hadoop requires a version of the snappy-devel package that is a lower one of that already present on the machine. In order to fix the problem you have to connect to the host and execute the following commands fro