Database Patterns

In the Database pattern the drive is processing a stream of requests to read and write 8KB random-address data blocks. The ratio of read to write requests is changing from 0% to 100% with a step of 10% throughout the test while the request queue depth varies from 1 to 256.

You can click the following link to view the tabled results for IOMeter Database pattern.

We will build diagrams for request queue depths of 1, 16 and 256.

The drives form two groups when working under low loads. One group includes Seagate HDDs whose graphs are almost straight lines. As opposed to them, the Hitachi and Fujitsu have a curve in the middle of the graph. As a result, the 7200.2 series drives from Seagate are ahead at low percentages of writes whereas the Hitachi and Fujitsu are better at high percentages of writes (80% and 90% from total requests).

The Hitachi should be called the overall leader here as it is but slightly slower than the Seagate team at reading but faster than them at writing. The Fujitsu is the loser, delivering rather low results throughout the test, excepting at 100% writes.

Comparing the different drives from Seagate, we can see that the new generation has become faster at random reading. Interestingly, the 160GB model is somewhat better at high percentages of writes than the other products from this brand.

The shape of the graphs remains largely the same at a queue depth of 16 requests. Everything we’ve said above becomes even more conspicuous. For example, the Seagate 7200.2 drives are faster than the others until high percentages of writes. The Fujitsu is the obvious loser, especially under the most complex load (when there is about the same share of read and write requests).

Take note of the difference of the 160GB Seagate from its 200GB series mate: the former speeds up at pure random reading.

When the request queue gets longer, the peculiarities we’ve noticed become even clearer. The Hitachi and Fujitsu are much better at 100% writes, the 160GB Seagate is excellent at 100% reads, and the Fujitsu slows down at medium loads.

The following diagrams show the performance of each Seagate drive at five queue depths.

The 7200.1 drive has the same shape of the graphs as the 200GB 7200.2 model, but the 160GB 7200.2 drive differs from them at high percentages of reads.

Here are the same diagrams for the other two drives:

• IOMeter: Database, Fujitsu MHW2 BJ, 160GB
• IOMeter: Database, Hitachi Travelstar 7K200, 200GB