Chapter 6: Managing Logical Drives and Hot Spares ● 74Changing the Read Cache SettingWhen read caching is enabled, the controller monitors the read access to a logical drive and, if itsees a pattern, pre-loads the cache with data that seems most likely to be read next, increasingperformance.● Enabled—The controller transfers data from the logical drive to its local cache in portionsequal to the stripe size. Use this setting for the best performance when workloads aresteady and sequential. Enabled is the default setting.● Disabled—The controller transfers data from the logical drive to its local cache in portionsequal to the system I/O request size. Use this setting for the best performance whenworkloads are random or the system I/O requests are smaller than the stripe size. (Formore information about system I/O requests, refer to your operating systemdocumentation.)To quickly change the read cache setting:1 Click the logical drive you want.2 In the menu bar, select Actions, click Configure read cache, then select Enabled orDisabled as required.The read cache setting is changed.Changing the Initialize PriorityThe Initialize Priority setting determines the priority for the initialization of the logical drive.The default setting is High, which means that the logical drive is initialized as quickly aspossible.Changing the Initialize MethodThe Initialize Method setting determines how a logical drive is initialized (prepared for readingand writing), and how long initialization will take. The settings are presented in order ofslowest to fastest method.● Build—(slowest) For RAID 1 logical drives, data is copied from the primary drive to themirror drive; for RAID 5 logical drives, parity is computed and written. Build is the defaultsetting for most logical drives (see Quick method below).Adaptec Storage Manager performs build initializations in the background; you can usethe logical drive immediately.● Clear—Every block in the logical drive is overwritten, removing all existing data. You can’tuse the logical drive until the initialization is complete.● Quick—(fastest) The logical drive is made available immediately. Quick is the defaultsetting for RAID 1, RAID 1EE, and RAID 10 logical drives.
