HP Surestore Disk Array FC60 HP SureStore E Disk Array FC60 - (English) Advanc - Page 302

Disabling Disk Module Write Cache Enable (WCE) Note To ensure optimum protection against data loss, it is recommended that Write Cache Enable be disabled on all disks in the array. Disabling disk WCE will impact disk array performance. However, it reduces the potential for data loss during a power loss. To ensure optimum data integrity, it is recommended that the Write Cache Enable (WCE) feature be disabled on all disk modules in the array. Each disk has internal write cache memory which is used to store data until it is written to the disk media. (This should not be confused with the array controller write cache, which is protected by the BBU.) If power to a disk is interrupted before data in write cache has been copied to the disk media, the data will be lost. To avoid this situation, the WCE feature should be disabled on all disks in the array. This ensures that data is written directly to the disk media and not stored in disk cache. This procedure for disabling disk WCE should be executed any time a disk module is replaced or a new disk module is added to the array. This will ensure that WCE is disabled on all disks in the array. To disable WCE on all disks, type: amutil -w WCE will be disabled on all disks visible to the array controllers. Depending on the number of disk modules in the array, this command can take up to 60 seconds to complete. Command Example The following example disables WCE on all disks in disk array 0000005EBD20: amutil -w 0000005EBD20 302 Managing the Disk Array Using Array Manager 60