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 […]