18 Performance Tuning; Analyzing And Tuning A System - HP 3PAR StoreServ 7200 2-node Administrator's Manual

18 Performance Tuning

Analyzing and Tuning a System

The tunesys command analyzes your entire system and automatically corrects space usage
imbalances in the system. Virtual volume and physical disk capacity are analyzed and rebalanced
for optimal performance. Access to the virtual volumes is not interrupted during the system tuning
operations.
Analyze and tune the system by issuing the tunesys -nodepct <percentage> -chunkpct
<percentage> -diskpct <percentage> command, where:
-nodepct <percentage> controls internode tuning. Virtual volumes are analyzed for
balance between nodes. If any node has an imbalance of more than <percentage>, the
virtual volume will be rebalanced. The threshold <percentage> must be between 1 and
100. The default value is 3.
-chunkpct <percentage> controls intranode tuning in conjunction with the -diskpct
option. Specifies that if a physical disk contains -diskpct <percentage> more chunklets
than average for the same device type, chunklets from the overused physical disk can be
moved to under used physical disks associated with the same node. The threshold -chunkpct
<percentage> must be between 1 and 100. The default value is 5. This option cannot be
used with the -cpg option.
-diskpct <percentage> controls intranode tuning in conjunction with the -chunkpct
option. Specifies the percentage of disks identified by the -chunkpct <percentage>
option required to initiate moving chunklets from overused physical disks to under used physical
disks on a node. The threshold -diskpct <percentage> must be between 1 and 100.
The default value is 10. This option cannot be used with the -cpg option.
Other options for controlling the tunesys command:
-cpg <cpg_name|pattern> limits the tunesys operations to the specified CPGs. The
specified CPGs must all be in the same domain as the CLI user. The -cpg option cannot be
used with the -nodepct <percentage> and -chunkpct <percentage> options.
Intranode tuning does not take place if the -cpg option is specified.
-maxchunk <number> indicates the maximum number of chunklets that can be moved from
any PD in a single operation. The <number> must be between 1 and 8. The default value is
2.
-tunenodech limits chunklet level rebalancing to the intranode level.
-dr indicates the command is a dry run and no tuning operations are performed. Use the
showtask command to view a summary of the analysis and rebalancing operations.
-maxtasks <number> specifies the maximum number of individual tuning tasks the tunesys
command can run simultaneously. The <number> must be between 1 and 8. The default value
is 2.
-waittask specifies that all tasks created by the tunesys command will complete before
returning.
-f specifies the system will not ask for confirmation before initiating the tunesys command.
You can schedule, monitor, and manage the tunesys command operations as a system task. For
information about system tasks, see
For more information about when to use the Dynamic Optimization feature and the tunesys
command, see the HP 3PAR StoreServ Storage Concepts Guide.
"Managing Tasks" (page 126).
Analyzing and Tuning a System 173