Backend processes in a storage system are implemented using a plurality of worker threads that are divided into two thread groups: thread group A and thread group B. Threads of thread group A are able to be used to process both Random Read Miss (RRM) workload items and Random Write Miss (RWM) workload items. Threads of thread group B are divided into two thread sub-groups: thread sub-group B1 and thread sub-group B2. Threads of thread sub-group B1 are able to be used to process both RRM and RWM workload items, while threads of thread sub-group B2 are reserved to be used to process only RRM workload items. The size of thread sub-group B2 relative to the size of thread sub-group B1 changes over time (from 0 threads to all threads of thread group B), depending on the duty cycle of the threads of group A.