Apple Keyboard Setup for Jetbrains Products Utilizing the OS X Keymap under Centos 7

On linux (Centos 7.1 to be specific) to effectively utilize Jetbrains’ products using an Apple keyboard with OS X hotkeys, the “F” keys need to be enabled and the command key (⌘) needs to be mapped to the “Meta” key code. Below are steps to do both of those things. 1. Enable the “F” keys. […]

Setting up an Environment to Build the Hadoop Native Library

The following are my notes on how to setup a freshly installed Centos 6.5 machine to compile the Hadoop native library. My reason for doing this was to add a modified version of the native library which utilized hardware compression. In order to accomplish that, I needed to recompile the native library. In a previous […]

Integrating Hardware Accelerated Gzip Compression into Hadoop

  The following is a set of instruction for integrating HW GZIP compression into a Hadoop DataNode. The compression enabled in this set of instructions is activated on the map phase’s output data, as well as the reduce phase’s output. Compression at the map output’s stage reduces the number of the bytes written to disk […]

Create a bootable CentOS USB drive with a Mac (OS X) for a PC

1. Visit Centos’ web page,, and download the iso image you’d like to boot from. 2. When the download has completed, open up terminal and use ‘hditutil’ to convert the *.iso to an *.img file (specifically, a UDIF read/write image). $hdiutil convert -format UDRW -o target.img CentOS-7.0-1406-x86_64-Everything.iso Reading Master Boot Record (MBR : 0)… […]

Verifying Intermediate Map Output Data is Compressed in Hadoop

Note: This is a really old post, and no longer demonstrates how to verify compression.  As mentioned by Edan in the comments below, compression can be verified by observing the differences between “Map Output Bytes” and the “Map Output Materialized Bytes” at the conclusion of a job. If you’re looking for the actual intermediate compressed data on […]

Linux X11 Forwarding Bug Workaround

To resolve errors regarding X11 forwarding open /etc/default/ssh and set: SSHD_OPTS= to SSHD_OPTS=-4 Next you’ll need to restart ssh /etc/init.d/ssh restart After ssh has restarted your issues will have been resolved.  Things like gvim, xterm, synaptic, or firefox are now possible over an ssh connection. The sort of errors that this alteration will fix look […]