A bandwidth control method, the bandwidth control method comprising: determining a target bandwidth expected when a first application uses a storage device; calculating a bandwidth difference between the target bandwidth and an allocation bandwidth allocated to the first application by the storage device; in response to a determination that the bandwidth difference is positive, such that the target bandwidth is a bandwidth greater than the allocation bandwidth, determining the difference between the target bandwidth and the allocation bandwidth; determining the number of zones corresponding to the difference between the target bandwidth and the allocation bandwidth; determining whether the number of the zones is available in a free zone pool; in response to determining that the number of the zones are not available in the free zone pool, adjusting the number of zones in the free zone pool and determining the number of the zones corresponding to the difference based on the adjusted number of the zones in the free zone pool and adjusting the allocation bandwidth to the target bandwidth by allocating the number of the zones to the first application, wherein adjusting the number of zones in the free zone pool comprises: determining whether there is at least one other application of which zones are able to be released; and in response to determining that there is not at least one other application of which zones are able to be released, determining all zones in the free zone pool as the number of the zones corresponding to the difference, characterized in that determining whether there is at least one other application of which zones are able to be released comprises determining, for a second application, whether bandwidth of the second application has previously been reduced, and in response to determining that bandwidth of the second application has previously been reduced, determining that zones of the second application are not able to be released. determining a target bandwidth expected when a first application uses a storage device; calculating a bandwidth difference between the target bandwidth and an allocation bandwidth allocated to the first application by the storage device; in response to a determination that the bandwidth difference is positive, such that the target bandwidth is a bandwidth greater than the allocation bandwidth, determining the difference between the target bandwidth and the allocation bandwidth; determining the number of zones corresponding to the difference between the target bandwidth and the allocation bandwidth; determining whether the number of the zones is available in a free zone pool; in response to determining that the number of the zones are not available in the free zone pool, adjusting the number of zones in the free zone pool and determining the number of the zones corresponding to the difference based on the adjusted number of the zones in the free zone pool and adjusting the allocation bandwidth to the target bandwidth by allocating the number of the zones to the first application, wherein adjusting the number of zones in the free zone pool comprises: determining whether there is at least one other application of which zones are able to be released; and in response to determining that there is not at least one other application of which zones are able to be released, determining all zones in the free zone pool as the number of the zones corresponding to the difference, determining whether there is at least one other application of which zones are able to be released; and in response to determining that there is not at least one other application of which zones are able to be released, determining all zones in the free zone pool as the number of the zones corresponding to the difference, characterized in that determining whether there is at least one other application of which zones are able to be released comprises determining, for a second application, whether bandwidth of the second application has previously been reduced, and in response to determining that bandwidth of the second application has previously been reduced, determining that zones of the second application are not able to be released.