| 摘要 |
A method for reducing the apparent response time for write I/O operations initiated by a host system (147) to a RAID level 3, 4 or 5 disk array including a spare disk drive comprises the steps of (1) saving write data received by the disk array from the host system directly to the spare drive, (2) issuing a write complete status signal to the host system (147) indicating completion of the host write I/O operation, thus freeing the host processor to perform other functions, and (3) transferring the data saved to the spare drive to the active drives within the array. This third step may be executed at any convenient time following the second step. For example, in systems where a host processor functions as the array controller, this third step may be delayed while higher priority tasks are executed. In systems where the disk array includes an array controller, the array controller coordinates the execution of this third step with other controller or array operations to optimize array operation. In addition , the data from multiple write I/O opertions may be accumulated to the spare drive prior to the step of transferring the data saved to the spare drive to the other, active, drives within the array. <IMAGE> |
