There are some informal policies governing the computer lab. Nothing is written in stone because we understand the need to be flexible, but the basic principle is to be reasonable in usage and considerate to other users.
Some people may like to run jobs on the machines to do some computational work. This is perfectly fine. However, there are some guidelines to follow while you are doing it.
- Run your processes with a high "nice" value. This is a measure of process priority, where large values get lower priority. The highest value is 20, and we recommend using values of 15 or 20.
- Watch the memory usage of your processes. Each machine has 4 GB of RAM. If you notice that the machine you're running on is using all its memory, decrease your memory usage. When the machine has to use swap space for an involved computation, performance drops precipitously.
- Don't use all the computing capacity. Running one thread on all the machines is okay, but except during the night (12AM-8AM) don't use more than two per machine on average. During classes, cut back on usage or stop your jobs entirely.
- Store temporary files locally. If you use a temporary
file in your computations, keep it in the
/tmpdirectory. This reduces network usage and improves performance.
- Don't use long-running jobs. If your process is very long-lived, it can't be distinguished from an abandoned process just wasting resources. Design your program to do a finite amount of work and terminate, and don't keep processes running longer than 7 days.
At the moment there are no disk quotas. We have 8 TB of total disk space available for usage, and so far there is no issue of running out. Don't use it needlessly, though. If you get up towards 100 GB of usage, you should think about cutting back.
We provide a 200 page per month quota, but this is intended to be a maximum, not an average. If you regularly reach this limit or get close, please cut down on your printing.