An Exchange workload is an Exchange Server feature, protocol, or service that’s been explicitly defined for the purposes of Exchange system resource management. Each Exchange workload consumes system resources such as CPU, mailbox database operations, or Active Directory requests to run user requests or background work. Examples of Exchange workloads include Outlook Web App, Exchange ActiveSync, mailbox migration, and mailbox assistants.
There are two ways to manage Exchange workloads: by monitoring the health of system resources or by controlling how resources are consumed by individual users (sometimes called user throttling in Exchange 2010). Managing workloads based on the health of system resources is new in Microsoft Exchange Server 2013. Controlling how resources are consumed by individual users was possible in Exchange Server 2010, and this capability has been expanded for Exchange Server 2013.
You can customize the workload management settings if you want to change the default behavior of the feature for the needs of your environment.
Here a sample (emphasize on OWA, de-emphasize on IMAP):
[PS] C:> New-WorkloadManagementPolicy SRKKWorkloadManagementPolicy
[PS] C:> New-WorkloadPolicy SRKKOWAWorkloadPolicy -WorkloadType OWA -WorkloadClassification CustomerExpectation -WorkloadManagementPolicy SRKKWorkloadManagementPolicy
[PS] C:> New-WorkloadPolicy SRKKIMAPWorkloadPolicy -WorkloadType IMAP -WorkloadClassification Discretionary -WorkloadManagementPolicy SRKKWorkloadManagementPolicy
[PS] C:> Set-ExchangeServer -WorkloadManagementPolicy SRKKWorkloadManagementPolicy -Identity SRKK-CAS01
[PS] C:> Set-ExchangeServer -WorkloadManagementPolicy SRKKWorkloadManagementPolicy -Identity SRKK-CAS02
To confirm setting applied,
[PS] C:> Get-WorkloadManagementPolicy