Testbed and Methods

We will be comparing the new hard disk drive with the solution from Western Digital featuring similar technical specifications and claimed parameters: WD2500PD.

We will run all our tests in two work modes. In the first case we tested single hard disk drives performance for WD2500SD and WD2500PD. And in the second case we tested RAID 0 arrays of two HDDs. The WD2500PD HDDs are supplied with the default “quiet seek” set, however, we activated “fast” mode for them, because RAID Edition HDDs are shipped with fast seek as default.

RAID 0 arrays were built with the RAID controller integrated into the ICH5 South Bridge of the mainboard chipset.

The testbed was configured as follows:

• Albatron PX865PE Pro II mainboard;
• Intel Pentium 4 2.4GHz;
• 256MB PC2700 DDR SDRAM;
• IBM DTLA 307015, 15GB system HDD;
• ATI RADEON 7000 graphics card;
• Windows 2000 with Service Pack 4.

We used the following benchmarking software:

• WinBench 99 2.0;
• Intel IOMeter 2003.02.15;
• Xbit FC Test 1.0.

Performance in Intel IOMeter: DataBase Pattern

With the help of the DataBase pattern we measured how fast the tested HDDs could process requests of various queue depth and write requests of various size. During our tests we used 8KB data blocks with random address.

To make the obtained results more illustrative we built three graphs for the queue depth equal to 1, 16 and 256 requests.

We will start the discussion with the linear workload. The queue depth=1 allows the older WD2500PD drive to outperform its newer rival. Its advantage is clearly seen in the standard mode as well as in case of an array. However, if in the first case the maximum advantage is achieved when the number of write requests varies between 20% and 90%, then in the second case the significant advantage is only achieved when the writes share reaches at least 70%.

On the next graph we see the HDDs performance under the workload of 16 outgoing requests.

Again the WD2500PD drive is ahead of the WD2500SD in both cases: in case of a single HDD as well as in case of a RAID array. It is evident that WD2500SD is ahead of its rival only in one mode: during RandomRead.

The third case we are going to consider corresponds to 256 requests queue depth. Just like in the previous case WD2500PD appears faster. WD2500SD HDD outperforms its counterpart only in case of 0 writes.

Well, it is evident that WD2500SD hard disk drive cannot boast as aggressive lazy writing, as its “desktop” fellow. Also I dare suppose that WD2500SD features less aggressive read ahead, which allows it to prove faster during random reading.