swap max crashes

[CaveSpectre11]

Describe the issue

VPS with several masternodes running on it; the masternodes will randomly crash when the swapfile gets full.

Can you reliably reproduce the issue?

Not exactly; but it seems to occur when "used" is pegged 100% of swap file size. Without a swap file, i can recall seeing the issue with 3 or 4 masternodes running.

If so, please list the steps to reproduce below:

1. run lots of stuff.
2. watch it crash

Expected behavior

don't crash. Should catch the memory fault (or whatever the fault is) cleanly and stop with an error message; without corrupting the chain.

Actual behavior

crash

Machine specs:

• OS: Ubuntu 16.04 w/ $5 Vultr VPS. 3-5 Masternodes without a swap file; 16ish with 4gb swapfile. Sometimes 18ish with 6gb swapfile, sometimes not until 26 or so.