Managing Qos Rules; Assembling Vvs Into Vvsets; Determining The Values For Iops And Bandwidth For A System - HP 3PAR StoreServ 7200 2-node Administrator's Manual

A QoS rule can be enabled and disabled at any moment. Once a QoS rule is disabled, the IOPS
and bandwidth for the VVs in the VVset increases (if they were being delayed by the rule).

Managing QoS Rules

There is no limitation on the minimum number of IOPS and bandwidth that can be set on a giving
VVset QoS Rule. It is important that the workloads of the various applications be fully understood
before applying a QoS rule. HP 3PAR System Reporter can be used to make this determination.
The following best practices provide general guidelines only; details are beyond the scope of this
paper.

Assembling VVs into VVsets

VVsets group virtual volumes logically. Use cases for VVsets include taking simultaneous point-in-time
virtual copies of multiple volumes, and creating Remote Copy volume groups for write consistency
during replication operations.
Volumes that belong together because they are owned by the same application or because they
belong in the same virtual domain should be included in the same VVset. Even if a number of
virtual volumes are unrelated and do not need write consistency, you can group them to a VVset
so as to reduce the administrative overhead when managing them. This way the I/O profile of the
volumes can be managed by a single QoS rule for their parent VVset.
VVsets are especially useful in the deployment of HP 3PAR Priority Optimization, because QoS
rules in HP 3PAR Priority Optimization are defined on VVsets. HP strongly encourages the creation
of VVsets and group volumes logically on HP 3PAR StoreServ storage systems, if this is not yet a
common practice anway.

Determining the Values for IOPS and Bandwidth for a System

HP 3PAR Priority Optimization's QoS rules define limits for IOPS and bandwidth in absolute
numbers, not percentages. Because of this, the QoS administrator needs reasonably accurate data
on the system's maximum I/O and throughput capability. He also requires an accurate
understanding of actual I/O and throughput workloads exercise to the volumes that will have QoS
applied to them.
HP Presales can estimate the maximum front-end workload for a system in IOPS and bandwidth,
assuming a particular I/O size and a given ratio for read/write I/Os. With this information, QoS
rules can be defined per workload, ensuring that the total sum of IOPS or bandwidth does not
exceed what is sustainable by the system configuration if no oversubscription is allowed. Re-analysis
of the system's capability and re-adjustments of the limit values for any existing QoS rules must
take place in the following cases:
When upgrading the storage system with additional disk drives and/or nodes.
When making use of additional FC and/or iSCSI interface cards to the storage system.
When adding additional physical hosts of virtual machines with extra workloads to the storage
system.
When upgrading the host hardware to a newer generation that offers more CPU power and/or
memory (for example, from G6 to Gen8 Proliant blades), generating more IOPS and
bandwidth, or when hardware details change in a virtualized server environment.
When deploying a new generation of an operating system on the host like moving from
Windows Server 2003 to the Windows Server 2008 or Windows Server 2012 version, or
when moving from a 32-bit to 64-bit environment.
When deploying a new brand of generation of FC or iSCSI HBAs on the host that have specific
queue depth requirements.
160 HP Priority Optimization