ALR0640E The Loss of Signal Rate of port port name in device device name was measured to be measured value cnt/s, which violated the defined critical-stress boundary value of boundary value cnt/s.
Explanation
The Loss of Signal Rate measures the rate at which the port lost communication with its partner port. These types of errors usually indicate physical link problems, caused by faulty SFP modules or cables, or caused by faulty connections at the switch or patch panel. However in some cases this can also occur due to exceeding the maximum link distance between ports, for the type of connecting cable and light source. A threshold was defined on this metric, which causes the measured value to be compared to the defined boundaries for each set of performance statistics collected from the switch.
This message indicates that a threshold boundary violation occurred. In this case, the specified port in the storage system or switch has a Loss of Signal Rate value that is greater than or equal to the critical-stress boundary that was defined for the related threshold.
Action
The threshold violation might indicate that a hardware problem exists either for this port or for the connected port. However it could also simply mean that the connected port was reset somehow, for example by rebooting the host containing the HBA. Therefore, isolated errors should be ignored in most cases, but if the rate remains consistently high over time, this may be a cause for concern. Follow the trouble-shooting guidelines for the switch, and for the connected entity (storage system, switch, or server HBA).
Because isolated temporary errors can be ignored in most cases, consider enabling the alert suppression option "Suppress alerts unless the triggering condition has been violated continuously for a specified length of time" for this threshold. This can greatly reduce the number of unnecessary alerts.