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From Tim Bain <tb...@alumni.duke.edu>
Subject Re: [++SPAM++]: RE: : Re: WARNING log message to be removed
Date Thu, 09 Nov 2017 05:17:24 GMT
On Wed, Nov 8, 2017 at 7:29 AM, COURTAULT Francois <
Francois.Courtault@gemalto.com> wrote:

> Hello Tim,
>
> Understood for the temp store: it looks like a swap mechanism in case
> there is no more room in memory, right ?
>

Just to clarify: it's a swap mechanism in case there is no more room in
*the memory store*, not in memory overall. This is not for paging generic
heap content out to disk if the JVM runs out of heap, etc., and I believe
it's also not for paging out content if you overfill a persistence store
that happens to be backed by memory (though I've not investigated that
specific question). But yes, you understand the overall concept.


> Let's say that, in our configuration, we only set the memoryUsage limit
>  without specifying any storeUsage and tempUsage limit .
> In such case, does it exist a formula to calculate the tempUsage limit (
> eg tempUsage limit=f(memoryUsage limit) )?
>

In that case, no limit is applied, so you're allowed to write content to
disk right up to the point where the write fails (maybe spectacularly)
because there is no more available space on the volume.


> I ask you the question, because if we only set the memoryUsage limit to
> 128 mb (no storeUsage and tempUsage limits are set), the WARNING message
> disappears with the same available space on the disk.
>

Yes, the warning message disappears because you've taken the safety off and
told the broker that you're on your own, so it allows you to shoot yourself
in the foot if you so choose without trying to help you avoid doing so. The
net effect for you is the same (the broker won't prevent you from filling
the disk in either configuration), but in one case it tells you that
there's a potential for doing that, and in the other it doesn't attempt to
warn you.

Tim

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