Linux is somewhat unusual in that it dynamically kills large processes when it's running out of memory. You used to have to set limits to get that behavior. Because of it, I run a moderately large swap (~8 GB) and can watch large jobs drive swap usage up. Then I decide if I want them dead.
--dave On 2019-02-27 10:38 a.m., Stewart C. Russell via talk wrote: On 2019-02-27 10:02 a.m., Gary via talk wrote: I have kubuntu 18.04 with 20 gigs ram. Does anyone know what the optimum size swap area that I should have? I asked a question about this at a GTALUG Q&A a few years back. Basically what I remember was: * are you frequently running out of memory? If not, don't change anything. * depending on what applications you're running, there are various kernel parameters that govern swap behaviour. They're tuned for "typical" performance. * The OOM killer (out-of-memory process killer) can sometimes kill a task that's taking up what it thinks is too much memory. I sometimes get that with very large (or very badly thought out) OpenSCAD renders, and it can be annoying to have to work round it. OOM killer exists to keep the system stable, and doesn't care if your work isn't happening. Swap is more of a thing on smaller machines such as a Raspberry Pi. These days, you've always got enough memory + swap until you find that one job for which you don't. For me, that was trying to build MySQL (for someone else, I promise!) on a Raspberry Pi. cheers, Stewart --- Talk Mailing List [email protected]<mailto:[email protected]> https://gtalug.org/mailman/listinfo/talk -- David Collier-Brown, | Always do right. This will gratify System Programmer and Author | some people and astonish the rest [email protected]<mailto:[email protected]> | -- Mark Twain CONFIDENTIALITY NOTICE AND DISCLAIMER : This telecommunication, including any and all attachments, contains confidential information intended only for the person(s) to whom it is addressed. Any dissemination, distribution, copying or disclosure is strictly prohibited and is not a waiver of confidentiality. If you have received this telecommunication in error, please notify the sender immediately by return electronic mail and delete the message from your inbox and deleted items folders. This telecommunication does not constitute an express or implied agreement to conduct transactions by electronic means, nor does it constitute a contract offer, a contract amendment or an acceptance of a contract offer. Contract terms contained in this telecommunication are subject to legal review and the completion of formal documentation and are not binding until same is confirmed in writing and has been signed by an authorized signatory.
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