Database Pattern

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% throughout the test while the request queue depth varies from 1 to 256.

Few people would install high-speed databases on external media whose speed is of course low. That’s why we won’t analyze the results deeply. We’ll just show you a table with the results and focus on the most interesting facts using diagrams.

We will show you three diagrams as the most illustrative ones. One diagram is for the Transcend drive which is the only one based on a Samsung hard disk (to remind you, the rest of the external HDDs are based on Fujitsu’s hard disks). The second diagram is for the 300GB Teac connected via USB. This drive shows the typical behavior of most of the reviewed HDDs. The third diagram shows the same Teac but connected via eSATA. You can use the links below to see the other diagrams.

• Database: Fujitsu HandyDrive 250GB
• Database: Fujitsu HandyDrive 300GB
• Database: No-name external HDD 250GB
• Database: Teac HD-15-OTC 250GB
• Database: Toshiba PX1275E-1G04, 250GB

Comparing the first two diagrams you can see that this test depends on the hard disk installed within the external storage. Compared with the Fujitsu-based drive from Teac, the Samsung-based Transcend features higher scalability of performance depending on the request queue depth as well as a better behavior under the most difficult load when the amount of reads and writes is about the same. The Transcend is worse in terms of deferred writing efficiency, though.

You can also compare the performance of the Teac with the different interfaces. When connected via eSATA, this HDD is slower at long queue depths when there is a high percentage of writes, but more efficient at processing read requests. The fact is the eSATA interface, as opposed to the USB, supports requests reordering according to NCQ technology. It is this technology that ensures such a substantial growth of the graphs in the left part of the diagram when we switch from USB to eSATA.