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How a bandwidth reservation is applied to a policy varies depending on two factors, the global bandwidth rule and the number of policies running at once. These two factors lead to two possible scenarios.
Under the first scenario, more bandwidth is available than all the running policies. In this case, the available bandwidth is split evenly across all running policies, the same as the pre-OneFS 8.2 behavior.
In the second scenario, the global configured bandwidth is less than the sum of the per-policy configured bandwidth for the running policies. Therefore, SyncIQ is unable to provide all the policies the requested bandwidth. Under this scenario, an even split occurs of bandwidth across all running policies, until the requested reservation is met. The even split ensures that the policies with the lowest reservation meet their reservation before the policies with larger reservations, preventing starvation across the policies.
In this example, the total requested bandwidth of running policies is more than the global bandwidth reservation. For example, with a global bandwidth rule of 30 Mb and 3 policies running simultaneously:
In this scenario, enough bandwidth is not available for each policy to meet its reservation. Therefore, each policy is allocated 10 Mb, as illustrated in the following figure.
In this example, the total requested bandwidth of running policies is more than the global bandwidth reservation. However, ample bandwidth is available for some of the policies to meet their reservation. For example, with a global bandwidth rule of 80 Mb and 3 policies running simultaneously:
In this scenario, enough bandwidth is not available for each policy to meet its reservation, but enough is available for Policy 1. Therefore, Policy 1 is allocated its full reservation of 20 Mb, but Policy 2 and Policy 3 are allocated a split of the remaining bandwidth of 30 Mb each, as illustrated in the following figure.
In this example, the total requested bandwidth of running policies is less than the global bandwidth reservation, allowing additional bandwidth to be granted to policies. For instance, with a global bandwidth rule of 80 Mb and 3 policies running simultaneously:
In this scenario, enough bandwidth is available for each policy to meet its reservation, but additional bandwidth is available that is not granted. Therefore, Policy 3 is allocated its full reservation of 30 Mb, but Policy 2 and Policy 3 are allocated 25 Mb each, as additional bandwidth is available, as illustrated in the following figure.