System and method for managing storage requests issued from multiple sources in a distributed storage system utilizes different queues at a host computer in the distributed storage system to place different classes of storage requests for access to a virtual storage area network. The storage requests in the queues are processed using a fair scheduling algorithm. For each queue, when the storage requests in the queue exceeds a threshold, a backpressure signal is generated and transmitted to at least one source for a class of storage requests queued in one of the queues corresponding to that backpressure signal to delay issuance of new storage requests of that class of storage requests.