Soon after we posted the Seagate Cheetah 15K.3 HDD Review on our site, Adaptec released a new version of its driver for the 39320D controller. We had had some misgivings about the previous, ver.1.0.000.000 driver since our first review of a U320 hard disk drives (see our article called Seagate Cheetah X15 36LP U320 HDD Review: Ready for Ultra320 SCSI?), so we were glad to welcome the new version.

As you are going to see, the new driver makes the hard disk drive behave somewhat differently.

The second thing we would like to discuss in this article is the use of several drives on one channel. Half a year ago we wrote (see our article called Seagate Cheetah X15 36LP U320 HDD Review: Ready for Ultra320 SCSI?):

A not very new SCSI HDD, Seagate Cheetah X15 36LP, can read a 60MB/sec data stream and three drives like that connected to one SCSI channel have not enough interface bandwidth (Ultra160 features 160MB/sec throughput) to work at their utmost of their power (3*60=180). And theoretically this interface allows using up to 15 HDDs connected to a single cable.
Moreover, as the next generation of SCSI HDDs, which is about to appear, will raise the data density level (and, accordingly, the linear read speed), it turns out that the Ultra160 interface is becoming more of a bottleneck in the disk subsystem.

To prove once again our point of view, we tested Ultra160 and Ultra320 controllers processing streaming read requests.

Testbed and Methods

At first, we will examine the performance difference shown by Seagate Cheetah 15K.3 connected to Adaptec 39320 controller with the new drivers. We will do it in FileServer and WebServer patterns.

HDD benchmarks were run on the following testbed:

• ASUS P3B-F mainboard;
• Intel Pentium III (Coppermine) 600MHz CPU;
• 2x128MB PC100 ECC SDRAM by Hyundai;
• IBM DPTA 372050 host HDD;
• Matrox Millennium 4MB graphics card;
• Windows 2000 Pro SP2.

In the second part of the review, we will see the dependence of read speed shown by four Cheetah 15K.3 drives on the type of the SCSI controller when working with data blocks of different sizes. As we have expected the data transfer rate from the HDDs to exceed 133MB/s, we used a somewhat more “advanced” platform:

• Intel SE7501BR2 mainboard;
• Two Xeon 2.8GHz processors;
• 4x1GB PC2100 ECC DDR SDRAM;
• IBM IC35L018UWD210 host HDD;
• Windows 2000 Pro SP2.

And no 33MHz PCI here!

The four Seagate Cheetah 15K.3 were connected to Adaptec 29160N and 39320D controllers via one channel. In order to ensure that the workload got distributed evenly among the drives in the bunch, we created four “workers” in IOMeter with identical tasks. Every worker was sending requests to its own drive, thus simulating work of a “real” application. We started all the workers up at the same time and measured their total data transfer speed from all the drives through the controller into the RAM.

The controllers were used with the following driver versions:

• Adaptec 29160N – 4.10.4002;
• Adaptec 39320B – 1.0 and 1.1.

In our tests we used Seagate Cheetah 15K.3 HDDs with “0002” firmware.