Fstab – Why Swap Space Doesn’t Get Filesystem Check at Boot Time?

"Occasional guests need more memory" sounds like a good application of overcommitting memory. The idea is you assign each guest a large amount of memory (more than you can actually give out) because they're generally not using it. Then you do the math to ensure you have enough swap space that the guests can actually swap out to disk in the worst-case-scenario where they all actually do use all that memory.

The swap space goes on the host machine, and it needs to obey

host swap space = sum of all guest memory + recommended host swap space

in order for it to be safe.

So if you have 10 guests and 2 GiB of RAM, you could experiment with something like

• 512 MiB RAM per guest (512 * 10 = 5120 MiB total)
• 2GiB swap on the host

Meaning your host swap space should be at least 512 * 10 + 2048 = 7168 MiB to handle this safely, assuming you can dedicate 2GiB of swap to the host (for that little host memory, this is recommended).

Always test these kinds of setups first to make sure your machine can handle them. Benchmarking them is even better, and will allow you to experiment with different loadouts and choose the one that works best.

fsck has an option which makes it delay the automatic check when the laptop is on battery power; that is, if the filesystem is configured to check once every 30 mounts, it will interpret that as once every 60 battery-powered mounts. Most distributions have it enabled these days. However, it only checks for that at startup.

What you could do is, if the automatic check starts, remove the power supply from your laptop and then restart fsck by whatever way (hard reset, ctrl-c, ...)