Computing Resources at the SSCC

The SSCC makes a tremendous amount of computing power available to its members. This article will help you find the computing resource that can do the job you need done.

Winstat

Winstat is the SSCC's Windows Terminal Server farm. Windows Terminal Servers allow you to log in to a Windows server remotely with full access to both the SSCC network and the software installed on the server. Software installed on Winstat includes general purpose statistical programs like Stata, SAS, SPSS and R, special purpose statistical programs like HLM and NVivo, and general Windows programs like Microsoft Office, Adobe Acrobat, and Adobe Dreamweaver. Logging in to Winstat is also the easiest way to transfer files between the SSCC network and home or other locations.

The Winstat servers have two Intel Xeon Quad Core processors (for a total of eight physical processors) and 24 gigabytes of RAM. Winstat runs 64-bit Windows Server 2008, allowing programs to access very large amounts of memory. To ensure high performance for everyone, we ask that you use no more than half of the server's memory at a time (12 gigabytes).

If you'll be running long jobs you should be aware that Winstat sessions are disconnected after 24 hours without input from the user, and disconnected sessions are terminated after three hours. For longer jobs we recommend that you switch to Linstat. If the program you are running is not available on Linstat, we also have a special Winstat server set up for long jobs (though it is often very busy). Contact the Help Desk for more information.

For more information about Winstat, see Using Winstat, or simply log in and try it.

Lab PCs

The SSCC's computer labs, rooms 4218 and 3218 in the Sewell Social Sciences Building, have more than 50 powerful PCs with a variety of statistical software installed, including most of what's on Winstat plus some additional programs. They also have client programs installed for accessing all the SSCC servers. This makes the labs an excellent place to do research.

For more information about the SSCC's computer labs, see SSCC Computer Labs and Information for SSCC Instructional Lab Users.

Sensitive Data Enclave

If you are working with data that cannot be stored on a network, Data & Information Services Center (DISC) makes a Secure Computing Enclave available.

Linstat

Linstat is the SSCC's cluster of servers running Linux. It consists of three servers with a variety of statistical software installed, including Stata, SAS, SPSS and R. They also have the usual Linux utilities and compilers.

The Linstat servers each have two Intel Xeon Quad Core processors (for a total of eight physical processors), 48 gigabytes of RAM, and about 200GB of local temporary disk space. To ensure high performance for everyone, we ask that you use no more than half of the server's memory at a time (24 gigabytes). Exceptions can be made--contact the Help Desk if you need to use more memory.

For more information about using Linstat, see Using Linstat.

Condor

The SSCC's Condor flock is a group of 48 CPUs running Linux. It runs as a sort of batch system: jobs are submitted to Condor, and then assigned to the first available CPU. The job then gets exclusive use of that CPU until the job is done. Condor cannot be used for interactive jobs, but it's the ideal place for very long jobs that will run for days or weeks. It's also the best place for multiple jobs: SSCC members are welcome to run up to ten jobs at a time on Condor.

The SSCC Condor flock includes a variety of servers, most of which are older and less capable than the Winstat and Linstat servers. The Linstat servers will also run some jobs from the Condor queue. If you'd like to run a job on Condor but have specific hardware needs, contact the Help Desk.

There is a trade-off when using Condor: your job may be assigned to a machine that is slower than Linstat, but then you don't have to worry about Linstat getting busy. Also, if you submit your job to Condor it won't make Linstat busy for others.

For more information about Condor, see An Introduction to Condor. You can also submit Stata jobs to Condor from the web.

Flash

The SSCC's High Performance Computing Cluster, Flash, is designed for parallel computing. It is ideal for jobs that can be broken up into many pieces that are executed simultaneously. Most jobs run on Flash are written in FORTRAN and use MPI to handle the parallelization.

For more information about Flash, see Using the SSCC's High Performance Computing Cluster.

Which Server Should I Use?

Most SSCC members run their jobs on Winstat because they are comfortable with Windows, Winstat is convenient, and Winstat is quite capable of running most jobs.

The following are some situations which suggest another server would work better for your job than Winstat. Often this means using Linux, but learning to run jobs using Linux is easier than you probably think. Using Linstat will get you started.

I have to run a long job, but Winstat keeps disconnecting me.

If your job takes long enough that you're running up against Winstat's session limits, your job is better suited for Linstat or Condor. The long-job Winstat server is also a possibility, but it's often busy.

I need this job to finish as quickly as possible!

For most jobs, Linstat is the place they'll finish most quickly, though the difference between Linstat and Winstat is usually very small. Jobs submitted to Condor will usually take longer.

I need to run a long job, but it's not important how long it takes. I just want to start it and forget about it.

Condor is perfect in this situation.

My job looks like it will take weeks to run. Maybe longer.

Jobs that take weeks to complete are not unusual at the SSCC, though it does require researchers with deadlines to plan well ahead (assume your program will go wrong at least once). On the other hand, some jobs simply are not feasible.

If you're using software the SSCC supports, the first thing you should do is visit the Help Desk and make sure your program is as efficient as possible. Then submit it to Condor.

But if it still takes too long, your job may be a candidate for Flash. The job would need to be capable of being broken up into smaller jobs that can be run in parallel, and there would almost certainly be a good bit of programming involved. Learning to use Flash requires a substantial time investment, but may be the only option for certain kinds of problems.

I need to run lots of jobs at the same time!

Condor is absolutely ideal for running multiple jobs. Feel free to submit up to ten jobs at a time to Condor. You are also welcome to run one job on each of the Linstats, or to reserve some of the Lab PCs in 3218. However, please do not submit more than one job per server--see the SSCC Server Usage Policy.

Last Revised: 8/23/2011