HP 3PAR StoreServ Concepts Guide: HP 3PAR OS 3.1.3

random, and transactional, among others), with different I/O packet sizes on a single HP 3PAR
storage system. The use of QoS rules stabilizes performance in a multi-tenant environment.
Virtual Volume Sets
QoS rules operate on sets of VVs called VVsets. A VVset is an autonomic group object that is a
collection of virtual volumes. VVsets help to simplify administration of volumes and reduce human
error. An operation such as exporting a VVset to a host will export all member volumes of the
VVset. Adding a volume to the VVset will export the new volume automatically to the host or host
set.
VVsets have a number of use cases beyond reducing administration for their volume members.
Most HP 3PAR Remote Copy operations are performed on sets of virtual volumes called remote
copy volume groups. VVsets also enable simultaneous point-in-time snapshots of all volumes
contained in the set with a single command. Up to 8192 volumes can be part of a VVset.
The volumes in a VVset can have different RAID levels and sizes. VVsets can contain volumes with
different provisioning types, RAID levels, sizes, and CPGs.
Quality of Service Rules
HP 3PAR Priority Optimization software provides quality-of-service rules to manage and control
the I/O capacity of an HP 3PAR StoreServ Storage system across multiple workloads. Application
of the rules enables co-location of the data from workloads of different types such as sequential,
random, and transactional, among others, with different I/O packet sizes on a single HP 3PAR
storage system. The use of QoS rules stabilizes performance in a multi-tenant environment.
Mode of Operation
HP 3PAR Priority Optimization operates by applying upper-limit control on I/O traffic to and from
hosts connected to an HP 3PAR StoreServ Storage system. These limits, or QoS rules, are defined
for front-end input/output operations per second (IOPS) and for bandwidth.
NOTE: IOPS is a common performance measurement used to benchmark computer storage. It is
indicative of how many host I/O requests the array is receiving per second. It is typically stated
as a whole number, such as 50,000 IOPS.
QoS rules are applied using autonomic groups. Every QoS rule is associated with one (and only
one) target object. The smallest target object to which a QoS rule can be applied is a virtual volume
set (VVset) or a virtual domain. Because a VVset can consist of a single VV, a QoS rule can target
a single VV.
Every QoS rule has six attributes:
The name of the QoS rule is the same as the name of the VVset.Name
The QoS rule can be active or disabled.State
Sets the Min Goal and the Max Limit on IOPS for the target object.I/O
Sets the Min Goal and the Max Limit in bytes-per-second transfer rate for the target objective.Bandwidth
The limit for the target object can be set to low, normal, or high.Priority
The goals for the target object are determined by milliseconds.Latency Goal
When an I/O packet reaches the HP 3PAR StoreServ controllers, HP 3PAR Priority Optimization
takes one of the following actions:
• Pass the I/O packet to the domain or VV.
• Delay the I/O by stalling it in a private QoS queue that gets processed periodically.
• Return a SCSI queue-full (QFULL) message to the host.
Priority Optimization 61