HP 166207-B21 - Smart Array 5302/32 RAID Controller Reference Manual page 73

data, whereas a delete command applied to a logical drive deletes the logical drive structure as well as
the data.
Syntax:
<target> modify reenable [forced]
Example command:
=> ctrl slot=3 ld 1 modify reenable forced
Changing the controller cache ratio
The controller cache ratio setting determines the amount of memory allocated to read and write
operations. Different types of applications have different optimum settings. You can change the ratio only
if the controller has a battery-backed cache (because only battery-backed cache can be used for write
cache) and if there are logical drives configured on the controller.
Syntax:
<target> modify cr=#/#|?
where <target> is a controller, and #/# is the cache ratio in the format read percentage/write
percentage.
Example command:
=> ctrl slot=3 modify cr=25/75
Enabling or disabling the drive cache
On controllers and drives that support physical drive write cache, you can use this command to enable or
disable the write cache for all drives on the controller.
CAUTION:
power failure occurs during a write process. To minimize this possibility, use a backup power
supply.
Syntax:
<target> modify drivewritecache=enable|disable|? [forced]
where <target> is a controller that supports drive write cache.
Example command:
=> ctrl slot=5 modify dwc=enable
Enabling or disabling the array accelerator
If the controller has an array accelerator, you can disable or enable it for specified logical drives.
NOTE:
cache for other logical drives on the array. This feature is useful if you want the other logical
drives to have the maximum possible performance (for example, if the logical drives contain
database information).
Syntax:
<target> modify aa=enable|disable|?
where <target> is a logical drive.
Example command:
=> ctrl slot=3 ld 1 modify aa=enable
Because physical drive write cache is not battery-backed, you could lose data if a
Disabling the array accelerator for a logical drive reserves use of the accelerator
HP Array Configuration Utility 73