HP ProLiant DL288 Configuring Arrays on HP Smart Array Controllers Reference G - Page 80

LicenseKey, DeleteLicenseKey These options enable you to enter a 25-character license key to activate or uninstall some controller features. Hyphens can be entered, but are not required. PreferredPathMode The setting that you select for this option determines how the preferred I/O path to a particular logical drive is set for a redundant array controller that is in an active/active configuration. Not all controllers support this feature, and controllers in an active/standby configuration disregard this option. • Auto is the default setting for new configurations. In this case, the storage system automatically selects the I/O path from the redundant controller to the logical drive and dynamically load balances all paths. • Manual enables you to assign the logical drive to a specific redundant controller. If you select this setting, use the PreferredPath (on page 84) command to specify the path. If you are reconfiguring a controller and do not specify a setting for this option, the existing setting remains unchanged. ReadCache, WriteCache Enter a number between 0 and 100 to specify the percentage of cache that is to be allocated to drive reads or writes. The default value for both options is 50. The allowable cache ratios depend on the controller model and whether it has battery-backed write cache, as described in the following table. A "+" indicates that the specified cache ratio is allowed for that type of controller, while a "-" indicates that the ratio is not allowed. Read:write ratio 100:0 90:10 80:20 75:25 70:30 60:40 50:50 40:60 30:70 25:75 0:50* 0:75* 0:100 RA4x00 with 16MB cache RA4x00 with 48MB cache All other controllers with battery-backed write cache All other controllers without battery-backed write cache * The cache ratio percentages do not total 100 in these cases because the additional 16-MB or 48-MB cache modules are not used. Only the battery-backed write cache is used. HP Array Configuration Utility 80