Table of ContentsView in Frames

How Storage QoS works

Storage QoS controls workloads that are assigned to policy groups by throttling and prioritizing client operations (SAN and NAS data requests) and system operations.

What policy groups are

A policy group is comprised of one or more workloads and a performance limit that applies collectively to all workloads in the policy group. There are two types of policy groups:

User-defined policy group
Enforces a maximum throughput limit on the storage objects that belong to the policy group by throttling input/output (I/O) requests.
System-defined policy group
Manages internal work that the cluster performs.

You can view performance data for both types of policy groups. The names of system-defined policy groups start with an underscore.

What workloads are

A workload represents work that the cluster performs. There are two types of workloads:

User-defined workload
Represents the input/output (I/O) operations from clients to a storage object that belongs to a policy group. Storage objects can be:
  • SVMs with FlexVol volumes
  • FlexVol volumes
  • LUNs
  • Files (typically represent virtual machines)

I/O to storage objects that are not assigned to policy groups belongs to the "User-Default" workload.

System-defined workload
Represents internal work that the cluster performs. Storage QoS controls specific system operations to prevent them from interfering with client operations. Examples include storage efficiency operations and data replication operations.

You can view performance data for both types of workloads. The names of system-defined workloads start with an underscore.

The following illustration shows a user-defined policy group and a system-defined policy group. The user-defined policy group controls the user-defined workload, which represents the client operations from the application to the storage object. The system-defined policy group controls the system-defined workload, which represents the internal system operations that the cluster performs.

This graphic is described by the surrounding text.