7.4.1 Enabling Cache Optimizations

Use this option to enable the following cache optimizations on the controllers in your storage space. Apply cache optimizations independently as per controller or per logical drive basis.

Note: You cannot use controller caching and maxCache caching concurrently. Controller caching is available only if maxCache is not enabled on the controller. For more information about maxCache, see Working with maxCache Devices.


Option	Description
Cache Ratio	Sets the global Read:Write cache ratio.
Write Cache Bypass Threshold	Sets the write cache block size threshold, above which data is written directly to the drive. The property is applicable only for the non-parity logical drives. The valid threshold size is between 16 KB and 1040 KB and the value must be a multiple of 16 KB.
No Battery Write Cache	Enables write caching on controllers without a backup module.
Wait for Cache Room	Waits for cache space (if none is available) before completing the request.
Recover Cache Module	Recovers the failed cache module.
Global Physical Devices Write Cache Policy	Sets the write cache policy for the physical drives on the controller. CAUTION: Enabling drive write caching can improve performance. However, a power, device, system failure, or dirty shut down may result in data loss or file-system corruption.
Drive Write Cache Policy for Configured Drives	Sets the write cache policy for the configured physical devices on the controller Default: Allows the controller to control the drive write cache policy of all configured physical devices. Enabled: The drive write cache for the physical device will be enabled by the controller. Setting to enabled can increase write performance but risks losing the data in the cache on sudden power loss to all configured physical devices. Disabled: The drive write cache for the physical devices will be disabled by the controller. Unchanged: Sets the physical devices factory default policy for all configured drives.
Drive Write Cache Policy for Unconfigured Drives	Sets the write cache policy for the unconfigured physical devices on the controller Default: The controller does not modify the drive write cache of the physical devices. Enabled: The drive write cache for the physical device will be enabled by the controller. Setting to enabled can increase write performance but risks losing the data in the cache on sudden power loss to all unconfigured physical devices. Disabled: The drive write cache for the physical devices will be disabled by the controller.
Drive Write Cache Policy for HBA Drives	Sets the write cache policy for the HBA physical devices on the controller Default: The controller does not modify the drive write cache of the physical devices. Enabled: The drive write cache for the physical drive will be enabled by the controller. Setting to enabled can increase write performance but risks losing the data in the cache on sudden power loss to all physical devices. Disabled: The drive write cache for the physical devices will be disabled by the controller.

To enable cache optimizations on a controller:

In the Enterprise View, select a controller.
On the ribbon, in the Controller group, click Set Properties.
When the Set Properties window opens, click the Cache tab.
Adjust cache settings, as needed.
Click OK.

Enabling Cache Optimization for a Logical Drive

You can enable/disable cache optimization for each logical drive in your storage space:

In the Enterprise View, select a controller, then select a logical drive.
On the ribbon, in the Logical Device group, click Set Properties.
In the Controller Caching drop down-list, select Disabled or Enabled.
Click OK.