So it sounds like you are experiencing a hard hang on the standby. In cpview history mode leading up to the incident does free memory slowly decrease? Just wondering if the kernel has somehow managed to exhaust all free memory which would cause all user-space processes to hang/die (including getty for the console).
In hang situations such as these, making an attempt to determine whether the hang is occurring in Gaia/Linux driver or Check Point's custom kernel code can be very helpful. Let's start with Gaia/Linux:
Are you using the new 3.10 kernel? (uname -a from expert mode) My guess is yes and there are significantly newer NIC drivers in use by that new kernel.
Another hang cause can be getting stuck inside a hardware interrupt which can be caused by hardware or a driver. Since handling NIC traffic is by far the most common hardware interrupt operation on a firewall it is logical to look there. I'd suggest trying to simplify what the NICs and their Gaia/Linux drivers are trying to do on both firewalls and see if if impacts the problem by disabling:
1) Hyperthreading (adjust back to 6 instances for a 2/6 split via cpconfig)
2) Disable Multi-Queue if enabled
3) If they have been modified, set interface ring buffer sizes back to their default
If the hang is occurring in Check Point code, it will be a lot tougher to find. Might be interesting to run ips off and fw amw unload on just the standby and see if the problem stops happening (you'll need to run these again if you reinstall policy to the cluster). Obviously if a regular failover to the standby occurs the IPS and AntiBot blades will not be protecting your traffic there, so take that into consideration. Also try the following simplifications from the Check Point code side:
1) Disable monitoring & QoS blades on gateway if enabled, these features load up extra kernel drivers on the gateway
2) Disable SecureXL - Note that SecureXL cannot really be permanently disabled in R80.20 and later
3) Look at the output of the enabled_blades command, anything else you can disable?
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