[CentOS] what would be happen if swap partition is not?

Fri Jul 3 18:18:57 UTC 2009
Kwan Lowe <kwan.lowe at gmail.com>

2009/7/3 MontyRee <chulmin2 at hotmail.com>

>  Hello, all.
> I know the function of the swap and can make swap partion or file.
> But, if there is no swap partion at system, what would be happen?
> that makes the system unstable or not?
> I have one system that has no swap, but there was no problem until now.

Hate giving this answer, but "it depends."

You *can* run a system without page space, but you should really know what
you're doing before you do this. It can work for types of workloads, but can
get you into trouble in many situations.

If you do run without page space, you should configure the kernel overcommit
options. You should also configure your application ulimits so that they
behave more predictably in case they cannot allocate memory. You should also
verify that your applications can properly handle a failed memory request.

To your question:  For a well-known application, running without page space
can make it more reliable *if* (and a big IF) all other applications are
predictable.  For example, say you're running you're well behaved
application... Another process suddenly starts consuming memory. Your
application then tries to allocate some memory. It cannot, so it crashes.

There are a ton of threads about how large the page space should be, given
modern multi-gigabyte RAM spaces. There are threads about whether a page
file or page volume is better.  What's best will depend entirely on your
workload and requirements :)

As your post demonstrates, a page-less system can run fine. The bigger your
RAM space, the less likely you are to run into issues.
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