HP XP20000XP24000 Disk Array - Manual (Page 11)

2 About Auto LUN Operations
Components
To use Auto LUN, you need:
• the storage system
• the Auto LUN program product (Performance Monitor is required.)
• a WWW client computer connected to the storage system via LAN
To use Auto LUN, you must use the WWW client computer to log on to the SVP. When you are logged
on, the HP StorageWorks XP Remote Web Console program, which is a Java application program, will
be downloaded to the WWW client computer. You can perform Auto LUN operations in the Remote
Web Console window.
For details about requirements for WWW client computers, see HP StorageWorks XP24000 Remote
Web Console User’s Guide.
Cautions:
• If Performance Monitor is not enabled, you cannot use Auto LUN or Performance Control.
• Performance management operations (Performance Monitor, Auto LUN, and Performance Control)
involve the collection of large amounts of monitoring data. This requires considerable web client
computer memory. It is therefore recommended that you exit the Remote Web Console program
when not conducting performance management operations, to release system memory.
Overview of Auto LUN
Auto LUN enables you to optimize your data storage and migrate volumes on the storage system. Auto
LUN tuning operations can be used to balance resource utilization and resolve bottlenecks of system
activity.
Auto LUN to Balance Workloads
If I/O accesses from hosts converge on particular hard disk drives, the hosts might suffer from slower
response times. To overcome this situation, Auto LUN lets you migrate high-usage volumes to a low-usage
hard disk drive or a fast hard disk drive. Volume migration can balance workloads among hard disk
drives and thus remove bottlenecks from the system. Volume migration can also balance workloads
among disk processors, which control disk I/Os.
Note:
• Manual migration supports external volumes, but you cannot examine the estimated usage rate
after migration because the usage rates of external volumes cannot be collected. For details on
external volumes, see the HP StorageWorks XP24000 Performance Monitor User's Guide.
• Auto LUN operations are completely nondisruptive - the data being migrated can remain online to
all hosts for read and write I/O operations throughout the entire volume migration process.
Keep in mind that storage system-tuning operations can improve performance in one area while
at the same time decreasing performance in another. Suppose that parity groups A and B have
average usage values of 20% and 90%, respectively. Auto LUN estimates that if one volume
is migrated from parity group B to parity group A, the usage values will become 55% and
55%. If you perform this migration operation, the I/O response time for parity group B will
probably decrease, and the I/O response time for parity group A may increase, while the overall
throughput may increase or decrease.
• Auto LUN should be performed only when you can expect a large improvement in storage system
performance. Auto LUN may not provide significant improvement for cases in which parity
XP24000 Auto LUN Software User's Guide 11