X-bit labs

Mission "Defragmentation". Part 2: PerfectDisk (page 2)

Category: Storage

by Aleksey Meyev

[ 08/09/2007 | 01:01 PM ]

Testing Methodology

To estimate how much time the defragmentation took, we prepared the hard disk drives in exactly the same way as for our previous article. We did it by creating a greatly fragmented file structure with a total size of 23.83GB on a 32GB disk partition with a 4KB cluster. In other words, 75% of the hard drive capacity was filled.

Partition parameters prior to defragmentation:

• Volume size: 31.94GB
• Cluster size: 4KB
• Used space: 23.83GB
• Free space: 8.11GB
• Percent free space: 25%
• Total fragmentation: 30%
• File fragmentation: 61%
• Free space fragmentation: 0%
• Total files: 44593
• Average file size: 649KB
• Total fragmented files: 7050
• Total excess fragments: 22361

We used GetSmart tool to transfer this partition sector by sector to the tested HDDs. Thus, we made sure the data was absolutely identical on each HDD because the per-sector transfer maintained the original structure of files within the partition.

After that, the tested HDD was attached to a SATA port of the following computer:

• Intel Pentium 4 2.8GHz
• 512MB DDR2-533 SDRAM
• ASUS P5WD Premium mainboard
• Samsung SP0411N as the system disk
• Windows XP Professional SP2

Then, the following FC-Test script was launched on the PC:

Comment beginning
System С:\Program Files\RAXCO\Perfect Disk\PDCmd.exe D: /sp /w
Comment end

According to this script, the PC places a timestamp, starts defragmentation using PerfectDisk in command prompt mode, and then places a second timestamp when the defragmentation application completes its work. By subtracting the first timestamp from the second one we find the duration of the defragmentation procedure on the tested HDD.

The disk map of files distribution over clusters looked almost ideal after defragmentation:

There are no fragmented files left at all, the entire free space consists of adjacent sectors, which demonstrates a definite advantage of the PerfectDisk application over the defragmentation tool built into Windows XP OS. However, our today’s goal is not to compare the results of different defragmentation tools, but to compare the defragmentation efficiency on different hard disk drives. So let’s no go too far into discussing these results: knowing the PerfectDisk uses different defragmentation algorithms is more than enough for our today’s tests.

I would like to say a few words about the recurring test results within the interval where they fall. We performed 10 measurements on one of the tested hard disk drives, namely Samsung HD501LJ (without NCQ):

As you can see, the interval where the measurements belong, namely the difference between the minimum and the maximum values, is pretty small: you should really look closely to notice it on the diagram above. And in numeric values it equals 13 seconds, which is less than 1% of the measurement. We believe that these results are quite trustworthy.