Fast Aging and Memory Usage

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1

I recently upgraded a Thunder 1040 from 4.1.4 to 6.0.3. We use it for CGN. Afterwards we got a few complaints about VPN, SIP, and gaming losing connection. One complaint specifically mentioned the issue occurring every 15 minutes. Logs show “Fast aging is enabled, memory constraint is reached” about every 15 minutes. I feel this is probably the issue, but I haven’t found any documentation that helps with troubleshooting…

  1. What, exactly, does fast aging do?
  2. Is it customizable? I looked at other thresholds and don’t see anything labeled “fast aging.”
  3. Even if it is customizable, would I want to, or am I likely to cause more issues?
  4. More important than fast aging is the memory usage. The log says the fast aging threshold is ~778 MB. Device info consistently shows 1.5 GB available. So I shouldn’t hit the threshold, unless this is a spike that doesn’t reflect in the log. But why every 15 minutes?
2

You may wish to engage TAC on this for a deeper look at the device. The backup logs should allow them to identify the spikes and cause of Fast Aging.

That said, Fast Aging generally is triggered when session memory is <20% free, and the threshold is not customizable. How many concurrent sessions do you have?

Fast Aging causes more aggressive session timeout / session close, and can result in poor user experiences especially with those protocols listed. The 15 minute interval is an interesting trend. We can see CPU spikes every 15 minutes due to the periodic ShowTech generation, but that should have no impact to system sessions.