Workstation, File- and Webserver Patterns

The next three patterns imitate a more complex disk activity in a heavily loaded workstation and two types of servers. We’ll compare the HDDs using a performance rating which is calculated as the total of speeds at different request queue depths with appropriate weights.

The Workstation pattern simulates multiple applications working in parallel. Thanks to a large amount of system memory the OS caches quite a lot of accesses, and the HDD often has to write down only the results.

The first test uses the whole capacity of the Hard Disk, and the entire Maxtor DiamondMax 10 series is on the losing side, except for the earliest versions with their superb NCQ implementation. The Western Digital drive with updated electronics is the winner. As we noted in the previous section, it has a rather effective deferred writing that does not conflict with read requests. This helps it show high results at small request queue depths. As many as five drives – WD2500KS, Samsung SP2514N, WD2500JD, WD2500JB and Seagate ST3250824AS – are contending for the second place on the podium. They go neck and neck through the entire test, i.e. at every request queue depth. The third place goes to the two HDDs from Maxtor which are accelerating as the load grows.

Full-featured Native Command Queuing helps where classic deferred writing algorithms fail. Strangely enough, none of the Hitachi HDDs has a high speed in this test. The best average seek time and the support for NCQ do not help them get higher than the middle of the list. The two HDDs from Western Digital are just as fast – they had a slump in the graph for the Database pattern.

The identical capacity of the HDDs allows us compare them using a part of their storage space, which largely negates such a parameter as average seek time. So, we run the same test on a 32GB partition.

The reduction of the test zone improved the positions of the Maxtor DiamondMax 10 and Hitachi HDDs, but the overall situation didn’t change. There are but minor changes among the leaders: the WD2500KS together with the Maxtor 6B250S0 and 7B250S0 have got closer to the WD2500JS while the others have fallen behind. The Seagate ST3250624AS (a Barracuda 7200.8 with a 16MB buffer) loses even to its mates with an ATA interface despite having a better average seek time and NCQ. The ST3250824AS, on the contrary, is a step forward in comparison with the Barracuda 7200.8 and looks competitive against products from other manufacturers. So, we can see again how important firmware algorithms are for reaching high performance. A fast seek, high data-transfer rate, large buffer – none of this can compensate imperfect algorithms of look-ahead reading and deferred writing.