3PAR InForm® OS 2.3.1 Concepts Guide (320-200112 Rev B, February 2010)

12.4
System Tuner
3PAR InForm OS Concepts Guide InForm OS Version 2.3.1
the failure of a drive cage because its RAID sets use chunklets from different drive cages. A
volume with a magazine-level availability can tolerate the failure of a drive magazine
because its RAID sets use chunklets from different magazines. As applications and business
requirements change, it may be desirable to non-disruptively alter the availability
characteristics of existing virtual volumes.
■ Volume service level changes. In addition to non-disruptively altering RAID and
availability levels for a given volume or volumes, it may also be useful to change volume
parameters such as the disk filtering parameters applied when the volume was created.
Dynamic Optimization tasks can be performed with both the 3PAR InForm Command Line
Interface (CLI) and the 3PAR InForm Management Console. Refer to the 3PAR InForm OS CLI
Administrator’s Manual and the 3PAR InForm Management Console Online Help for
instructions on how to perform these tasks.
12.4 System Tuner
3PAR System Tuner is an optional feature that improves performance by identifying over-used
physical disks, and performing load balancing on those disks without interrupting access. You
must purchase the 3PAR System Tuner license to use this feature.
The InForm OS automatically creates a balanced system layout by mapping virtual volumes to
many logical disks, and creating logical disks from chunklets drawn from many physical disks.
The I/O for each volume is striped across many physical disks, increasing the throughput of the
volume. As the system grows and new applications are introduced, new storage usage patterns
can emerge and the system performance can degrade. 3PAR System Tuner maintains peak
system performance by automatically detecting and resolving bottlenecks without
interrupting access.
If the performance of one or more physical disks degrades, the throughput of the logical disks
is reduced and the entire system performance may decline. There are two general reasons why
a physical disk may have degraded performance:
■ The physical disk has reached its maximum throughput due to an unbalanced load. A disk
in this state typically has unusually high average service times when compared to other
disks.
NOTE: Using Thinly-Provisioned Virtual Volumes (TPVVs) requires the 3PAR Thin
Provisioning license, see 3PAR InForm Software on page 2.7.