Intense resource considerations in progress.

VirtualExam (vx)
Resource considerations

Because the VX environment runs remotely from the student actually sitting the exam, and because the environment runs on a shared server, some consideration of resources needs to be made when sizing the backend server or backend server pool, and determining if network capacity will be sufficient.

This page is not an answer page. More it's some things to think about…

Broadly speaking, the areas in which you might have resource problems include:

1. Memory
2. CPU
3. Disk space
4. Disk I/O
5. Network bandwidth

Memory

1. The ps command to see how much memory is actually being used by a process
2. Use small-footprint applications. For example, don't use Firefox when a lighter-weight browser is an acceptable alternative.
3. Image editors and video editors can use a lot of memory.

CPU

1. Consider whether sitting the exam requires running CPU-intensive processes - like compilers or computationally-heavy analyses.
2. Consider that one or more student processes may get stuck ina loop and use up all of one CPU.
3. How many CPU cores are there in the backend exam server?

Disk space

1. The VX environment itself doesn't use up much disk space at all because it mainly uses hard links and bind mounts to build the contents of the gaol.

Disk I/O

Heavy users of disk I/O:

1. Compilers
2. Database engines
3. File and disk searches

Network bandwidth

1. Animation
2. Image editors

ulimit?

Multiple backend exam servers and round-robin DNS

A possible solution to memory and CPU constraints.