Depending on a solid model’s complexity, OpenSCAD will sometimes chew through system memory, consume the entire swap file, and then fall over dead. In an attempt to work around that situation, I recently jammed a 32 GB USB drive into the back of the box, turned it into a swap device, and then told the kernel to back off its enthusiasm for swapping.
Format the USB drive as a swap device:
sudo mkswap /dev/sd?? #--- unmount it before you do this! Setting up swapspace version 1, size = 31265292 KiB no label, UUID=0f559a8c-67b7-4fa3-a709-17aeec3104c4
Add it to /etc/fstab and set swap priorities:
# swap was on /dev/sdb3 during installation UUID=e8532714-ad80-4aae-bee7-a9b37af63c8c none swap sw,pri=1 0 0 UUID=0f559a8c-67b7-4fa3-a709-17aeec3104c4 none swap sw,pri=5 0 0
Turn it on:
sudo swapon -a
Following those directions, dial back the kernel’s swappiness and limit the file cache growth:
sudo sysctl -w vm.swappiness=1 sudo sysctl -w vm.vfs_cache_pressure=50
Those commands now live in /etc/sysctl.d/99-swappiness.conf:
cat /etc/sysctl.d/99-swappiness.conf # Improve responsiveness by reducing cache swapping vm.swappiness=1 vm.vfs_cache_pressure=50
For whatever reason, WordPress turns underscores into blanks, so those obvious typos aren’t, really.
And then it should Just Work.
The box has 4 GB of RAM and, under normal circumstances, doesn’t swap at all, so I expect the USB drive should kick in only for extreme OpenSCAD models. The swappiness tuning should help during ordinary operation with large file operations.
I have no results to report, but if something blows up, I know what changed…
The Smell of Molten Projects in the Morning 