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NIC flaps due to high memory utilization on devices with 4GB of RAM

Article Number: 000001629
Published: February 23, 2017
When RAM and swap utilization goes high on the Exinda, it can have the impact of potentially causing the NIC bypass timers to time out, which will effectively make the NIC stop passing traffic for a short period of time. In this scenario, the following logs are usually seen:

Oct 31 14:33:03 exinda bypassd[4630]: TID 140102869018368: [bypassd.NOTICE]: br10 (silicom) Timed out. Reset state to Active (Clearing Bypass)
Oct 31 14:33:03 exinda bypassd[4630]: TID 140102869018368: [bypassd.NOTICE]: br12 (silicom) Timed out. Reset state to Active (Clearing Bypass)

This is typically seen on 4GB RAM devices that are running version 7 and are accelerating traffic.  After upgrading to version 7, the memory utilization will be much higher than version 6. The following illustrates the increase after an upgrade (taken from Monitor > System graphs):

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There are many reasons why RAM increases. The main reason why this would happen on a device with 4GB of RAM on version 7 is because, by default, version 7 by default has a higher memory footprint than version 6 - so RAM utilization will always increase after upgrading from 6 to 7.

An other cause could be a DDoS attack passing through the Exinda, which causes RAM to increase dramatically. This could potentially lead to NIC flaps as well.
Depending on the model type, RAM should be upgraded to 8GB+. If the model is a 2061 or 4010, then the RAM cannot be upgraded. ExOS 7.4.4u2 has helped to mitigate this problem. Please see the release notes for more information.

Please contact Exinda Support for further assistance if this problem is encountered.