Multi-Threaded Read & Write

The multi-threaded tests simulate a situation when there are one to four clients accessing the hard disk at the same time. The depth of the outgoing request queue is varied from 1 to 8. We’ll discuss diagrams for a request queue of 1 as the most illustrative ones. When the queue is longer, the speeds depend but little on the number of applications.

You can follow the links below for numeric data and a diagram with more threads:

• Data part 1 (click here)
• Data part 2 (click here)
• Read diagram for three and four threads (click here)

Multi-threaded reading has always been a hard test. Two simultaneous threads is already enough for the HDD to slow down. More threads don’t affect the drive’s performance much after that. The interface bandwidth is not important anymore but the firmware of the HDD affects performance greatly like in the Database test. In this test session, the Fujitsu HandyDrive, ZIV 2 and ZIV Pro cope best with the load as their speed lowers less than twofold.

Note that the Teac HD-15 PUS with a eSATA interface and the ZIV Pro with a FireWire interface have higher speeds with two threads than when connected via USB. It is because eSATA and FireWire offer better capabilities for processing the request queue.

The Seagate and Maxtor have poor results as their speed plummets sixfold.

• Data part 1 (click here)
• Data part 2 (click here)
• Read diagram for three and four threads (click here)

The Teac HD-15 PUS with an eSATA interface is the only drive to suffer a noticeable performance hit when writing several threads. This doesn’t prevent it from becoming the leader, though. The ZIV Pro with a FireWire interface should be noted as it accelerates by 2MB/s when writing two threads. The ZIV 2 is the only drive to slow down here, excepting the leader.