Introduction to Open Science Grid

Introduction to Open Science Grid (OSG)

The Open Science Grid (OSG) is a consortium of research communities who promote science via sharing of computing resources. The Open Science Grid (OSG):

• enables distributed computing on more than 120 institutions,
• supports efficient data processing and
• provides large scale scientific computing of 2 million core CPU hours per day.

The resources accessible through the OSG are contributed by the community, organized by the OSG, and governed by the OSG Consortium. The cores that are free in the OSG shared pool are made available to users. Opportunistic resources available at any given time will vary depending on usage by resource owners.

Computation that is a good match for OSG Connect

High throughput workflows with simple system and data dependencies are a good fit for OSG Connect. Typically these workflows can be decomposed into multiple tasks that can be carried out independently. Ideally, these tasks will download data for input, run some computation on it and then return results (which may be used by future tasks).

Jobs submitted into the OSG Connect will be executed on machines at several remote physical clusters. These machines may differ in terms of computing environment from the submit node. Therefore it is important that the jobs are as self-contained as possible by generic binaries and data that can be either carried with the job, or staged on demand. Please consider the following guidelines:

• Software should preferably be single threaded, using less than 2 GB memory and each invocation should run for 1-12 hours (optimally under 4 hours). There is some support for jobs with longer run time, more memory or multi-threaded codes. Please contact the support listed below for more information about these capabilities.
• Only core utilities can be expected on the remote end. There are no standard versions of software such as 'gcc', 'python', 'BLAS' or others on the grid. Consider using Distributed Environment Modules to manage software dependencies, or read our Developing High-Throughput Applications guide.
• Input and output data for each job should be < 10 GB to allow them to be transferred in by the jobs, processed and returned to the submit node. Note that the OSG Connect Virtual Cluster does not have a global shared file system, so jobs with such dependencies will not work.
• No shared filesystem. Jobs must transfer all executables, input data, and output data. HTCondor can transfer the files for you, but you will have to identify and list the files in your HTCondor job description file.

Computation that is NOT a good match for OSG Connect

The following are examples of computations that are NOT good matches for OSG Connect:

• Tightly coupled computations, for example MPI based communication, will not work well on OSG Connect due to the distributed nature of the infrastructure.
• Computations requiring a shared file system will not work, as there is no shared filesystem between the different clusters on OSG Connect.
• Computations requiring complex software deployments or proprietary software are not a good fit. There is limited support for distributing software to the compute clusters, but for complex software, or licensed software, deployment can be a major task.

##How to get help using OSG Connect

Feel free to contact the OSG Connect support team at: connect-support@opensciencegrid.org.