HP ProLiant 4000 Novell GroupWise Performance Management on Compaq Servers - Page 15

ECG007.0897 WHITE PAPER (cont.) 1...5 RAID 0 - No Fault Tolerance RAID 0 means that no fault tolerance is provided. The data is still striped across the drives in the array, but it does not include a method to create redundant data. If one of the logical drives fails, data on that drive will be lost. None of the logical drive capacity is used for redundant data, so RAID 0 offers the best processing speed, as well as capacity. RAID 0 is appropriate for applications that deal with non-critical data requiring high-speed access. Fault Tolerance Performance Comparison Performance (Seconds) 1200 1000 800 600 400 200 0 RAID 0 RAID 1 Fault Tolerance RAID 5 Figure 4. Fault tolerance performance comparison Novell/Compaq test results show a measurable difference in response time rates between RAID 1, RAID 5 and RAID 0. RAID 0 achieved the best performance, outperforming RAID 5 by 10-20% in response. Keep in mind that while RAID 0 utilizes available disk space most efficiently, this level offers no fault tolerance protection. Based solely on response time, the recommendation would be to use RAID 1 over RAID 0 because of the performance gains expected, combined with the hardware fault tolerance protection. RAID 5 would be for data that is not mission-critical, and would offer better usage of disk capacity than RAID 1. Smart-2 Controller's Array Accelerator Read/Write Ratio The Array Accelerator has a read/write cache ratio that can be customized to fit your GroupWise Server activity using the Compaq Array Controller Configuration Utility. The configuration utility assigns 4 MB of cache memory to read/write operations. Ratios of 0% Read/100% Write, 25% Read/ 75% Write, 50% Read/ 50% Write, 75%Read/ 25% Write and 100% Read/ 0% Write are possible.