[williamstein]

The typical usage pattern we have is somebody interactively using a SageMath worksheet over the course of an hour or two. Sage uses a lot of memory (large matrices, plots, etc.), and the state must be maintained in memory during the course of the calculation. Also, people will often open many worksheets, which spawn numerous processes. We use fork for Sage processes to keep down resource usage (maximizes shared memory). Each project is not in its own VM; instead we use cgroups extensively (similar technology that Docker uses under the hood) to control resource usage. All the CPU/memory of the free computers is typically maxed out, and being shared (controlled by cgroups) fairly between users. cgroups is awesome technology.

[bgwhn]

> Sage uses a lot of memory (large matrices, plots, etc.), and the state must be maintained in memory during the course of the calculation.

1. I thought sage used a ton of RAM partly because of the huge amount of statically linked libraries. I see you said you're using fork to maximize shared memory. Have you tried KSM (Kernel Samepage Merging)?

2. Have you looked at zram? Certain matrices and such may be easily compressible.

[williamstein]

Thanks -- these are both great ideas; I've opened a ticket: https://github.com/sagemathinc/smc/issues/93