How to measure HA?

Hi,

You can use the following information for your reference:
Mean time between failures (MTBF)
The fault occurrence probability is identified by HA. The index refers to the average time (expressed in hours) when a component or a device works without any failure.
Mean time to repair (MTTR)
The fault rectification capability is identified by maintainability. The index refers to the average time for rectifying the fault of a component or device. Actually, it refers to the error tolerance capability of the device. In the broad sense, MTTR also concerns spare parts management and customer service. It plays an important role in evaluating maintainability of a device. The MTTR calculation formula is as follows:
MTTR = Fault detection time + Board replacement time + System initialization time + Link recovery time + Route convergence time + Forwarding recovery time.

The smaller the previous values, the smaller the MTTR, and the higher the device availability.