Different Period/Sensitivity combinations

Answer

Period is the number of seconds between heartbeats.
Sensitivity is the number of missed heartbeats that constitute a failure.

For the above settings, the overall heartbeat time is the same, 16 seconds per the following formula :

(Period x Sensitivity) x 2

The primary difference is that with a Period of 1, there would be more heartbeat traffic, twice the number of IP packets sent out per node, compared to a Period of 2.

Here are 3 best practices to consider:

1) If for some reason your network bandwidth is very limited, using a higher period will reduce the number of heartbeat packets being sent out. However, it is considered better tuning practice (more precise tuning) to keep the period as low as possible, typically 1 (the default).

2) Tune (increase) the Sensitivity setting before thinking about increasing the Period. However if you get to the point of going double digits with the Sensitivity, then its time to increase the Period from 1 to 2. For example, instead of choosing the following:

Period=1
Sensitivity=14
[Overall heartbeat timeout of 28 seconds]

... increase the Period to 2 and set the Sensitivity to 7 [overall timeout will still be 28 seconds]

3) Do not set Period value greater than Sensitivity. Say you set Period to 14 and Sensitivity to 2, this would mean RSCT sends out a heartbeat once every 14 seconds, but it also means that it only takes 2 misses for there to be considered a failed heartbeat. This is considered very imprecise measuring/tuning and not recommended.