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Paul KonstanskiFlag for United States of America

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Linux Real Time Memory on Distinct 24 Cycle

In a previous question I explained a problem I was having with MySQL memory. I took many of the recommended steps and have seen some improvement.

But the regular cycle I'm seeing has become even more pronounced.  If you look at the attached image, you'll see that the Real Memory climbs for 24 hours then does a drastic drop right around 3:30am EST.

I was able to take a picture of memory allocation right before and after the drop which is shown in the image.  You'll notice that the big changed occurred in the "Slab" and "SReclaimable" listings.

I'm trying to understand a few things.

  • What might contribute to the steady increase in Slab & SReclaimable throughout the day.
  • How do I find what is causing it to be "cleaned out" at 3:30am every day.
  • What logs or processes can I monitor/provide that will assist with discovering what is happening.

Thank you.

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Here's what the memory now looks like five hours after the reset.

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gheist
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SReclaimable is disk read cache
what does mysqltuner sat about your mysql sizing?
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Here is a screen shot of mysqltuner...

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Still quite bewildered with what is happening. This cycle continues.
you can
watch free
I assume it is disk cache growing http://www.linuxatemyram.com/
What I'm trying to identify is "why the cycle." What is it that happens at the same exact time every day that causes the memory to drop so sharply. If I can identify that, I can then do some reverse tracking to see what quickly begins to build the memory use.  I've checked all of my cron jobs that run at or near that time, but none of them cause the memory to drop when I manually run them.

So there is something else that happens at that time every day that cause the memory to drop.

I'm trying to see which specific applications are causing the memory use to grow and then what causes it to decrease so rapidly.
syslog has cron events.