I understand now, thanks for your patience. Unfortunately, this means that the only way for this to work is having the Gurobi libraries' code and incorporating mmap there, because that's where the memory-heavy node-files are created and put in memory. I don't know anything about their product, so it might be worth raising the issue with them. Too bad this is not open-source software, and therefore this is impossible. Is there an alternative to mmap to perhaps squeeze some extra space in the disk? No, not really. The limit you’re hitting is actually a system-wide cap enforced by the kernel. You're hitting it because your single process is using an extraordinarily large amount of memory, but you'll see exactly the same failure with more processes using smaller amounts of memory. I was wondering if renicing the process to, say, -20, can have some indirect benefits... No, not really. Theoretically, you could free up some additional memory by reducing total system activity, but you're using so much memory