patas.ling.washington.edu Condor Cluster

What is it?

Condor is a batch-oriented clustering system. Jobs are submitted into a job queue, matched with an available compute node, and run on that node.

How is it different from OpenMosix?

If you've used our Pongo OpenMosix cluster, you may be wondering how Condor differs. There are some key differences:

• OpenMosix attempts to be transparent to the user. Processes are all run on the head node, and they are then migrated to available compute nodes. By contrast, Condor requires the user to set up the job specifically to be run on the cluster. (The software, however, does not need to be cluster-aware.)
• OpenMosix jobs can be interactive; Condor jobs must run without user interaction.
• OpenMosix cannot migrate jobs that use threads or shared memory, and jobs sometimes crash during migration. Condor can run any software that can be set up to run non-interactively, and it will have the same stability it would on a stand-alone system.

How do I get an account?

If you have a pongo account, you already have access to the Condor cluster. ssh to patas.ling.washington.edu.

If you do not yet have a Computational Linguistics account, fill out our online account request form. You must have a valid UW NetID.

How do I use it?

Visit the HowToUseCondor Wiki page for a quick introduction. You may also want to view the PDF presentation I wrote for orientation.

Software notes

This section documents differences between the software loaded on patas and the software loaded on pongo.

• The base operating system is Red Hat Enterprise Linux Server 5, instead of Debian Stable.
• We are running a 64-bit operating system, with compatibility libraries to support 32-bit software.
• The 64-bit version of Sun's Java Virtual Machine is installed. This provides nearly 4 gigabytes of heap space, instead of 2 gigabytes in the 32-bit version. This is also a server JVM, meaning it performs some extra optimization. This results in slower startup times but long-running jobs complete faster.
• To encourage efficient use of the cluster, as well as to make sure the system stays responsive, long-running jobs on patas itself will automatically have their CPU priority lowered. Jobs submitted to Condor are immune from this and always run at full priority.

Linguistics software

A listing of linguistics software on Patas can be found in the CompLing database.

Patas? What's that?

Patas monkeys (pronounced "pä'təs") are slender, ground-dwelling primates found in central Africa. They can run faster than any other primate, reaching speeds of up to 55 km/hr.

-- DavidBrodbeck - 20 Nov 2007