3 Enterprise Disk Defragmenters

Monitors are getting thinner, CPUs are becoming faster, and software is getting easier to use. But one aspect of computing that remains the same is hard disk fragmentation. Our OSs—for various reasons— are failing to store files in contiguous disk space and are instead tossing parts here and there, filling in disk gaps willy-nilly. Our poor hard disks have to read portions of files scattered all over the platter, rather than reading files in smooth, continuous motions.

So, you need a defragmentation tool. Where do you start? We’ve selected three products for a comparative review—Diskeeper’s Diskeeper 2008 Server, O&O Software’s O&O Defrag 10 Server Edition, and Raxco’s PerfectDisk 2008 Server—that should help you decide which best suits your environment.

All three companies also offer workstation editions (and even products for Exchange Server, SQL Server, and Windows Home Server), but I found few differences between these server and workstation versions. The primary goal of both is to simply defragment a computer’s hard disk. However, the server versions in this review either come with built-in enterprise functionality or offer a separate add-on to help you centrally manage your defragmentation tasks.

Testing
To permit straightforward comparison of the products’ features, I used VMware Server 1.0.4 to install each product on a virtual machine (VM). However, I also felt it was important to install each product on actual hardware to compare performance results, so I did that, too. To ensure that I compared the products fairly, I used disk-imaging software to capture a heavily fragmented hard disk with only 20 percent free space. In addition, I included one extremely fragmented file that was larger than the free space, as well as one heavily fragmented disk with a lot of free space. In just a few minutes, I could easily reproduce the fragmented drives for testing. Then, I used each product to run one manual defrag pass on the hard disk. You can find the results in Table 1.

Product Overview
All three products offer offline and online defragmentation. Offline defragmentation occurs on files that are in use while the OS is running. Files that can be defragmented only while the OS isn’t running include the Master File Table (MFT), the hibernation file, and the paging file. Only Diskeeper and PerfectDisk let you schedule an offline defrag.

The products differ in their online defrag approach—that is, defragmenting files while the system is running. Both PerfectDisk and O&O Defrag take a scheduled defrag approach, and they both have wizards to help you automate the scheduling process. Diskeeper constantly runs in the background.

If you need to deploy and manage defrags on multiple systems from one central location, take a close look at each product’s functionality in this area, because each one offers something different. O&O Defrag includes a Network Management tool (with the Server edition), Diskeeper offers an add-on product called Diskeeper Administrator, and Perfect- Disk (as of this writing) is working on a new product called Command Center. (According to the company Web site, Command Center will be available to PerfectDisk 2008 customers at no additional charge.)

PerfectDisk and Diskeeper both work with Microsoft Volume Shadow Copy Service (VSS). When a disk defragmenter moves enough data around the disk, VSS can mistakenly assume that a file change has occurred, and thus take a snapshot. Both of these products let you to make the system “VSS aware” so that unnecessary snapshots don’t occur.

Diskeeper
I started the application by double-clicking the desktop icon. The opening screen is immediately overwhelming, particularly compared with the GUIs of the other two products. Instead of easy-to-read labels, Diskeeper has cryptic icons that you must “hover” your mouse over to see what they do. Perhaps I’m being picky, but my initial impression was that the other two products offer much simpler interfaces. On a brighter note, a Quick Start Guide in the interface’s left pane helps get you started in the right direction. Figure 1 shows the Diskeeper interface.

Defragmenting. Diskeeper is unique in that it offers not only classic online and offline defragmentation that you can set manually and schedule, but also a new method called Automatic Defragmentation (which debuted in Diskeeper 2007). Automatic Defragmentation runs silently in the background to ensure that all your hard disks stay defragmented. My first concern was that this feature would consume valuable resources from the server. But Diskeeper uses InvisiTasking technology to monitor disk I/O, memory allocation, and CPU usage to ensure that Diskeeper never negatively affects your users. Automatic Defragmentation will even choose the appropriate engine to use, depending on the kind of fragmentation you have (e.g., heavy fragmentation, low free disk space).

Letting disk-defragmenter software run in the background and configure itself is a new concept to most administrators. Offline and online manual defragmentation is available, but it isn’t necessary to run; you can just install it and have a nice day.

Above and beyond. What sets Diskeeper apart from the other two products is the Automatic Defragmentation feature, ensuring that your systems are always in an un-fragmented state. Another interesting feature is Intelligent File Access Acceleration Sequencing Technology (I-FAAST). This feature, according to Diskeeper, sequences files to take best advantage of the logical and physical characteristics of a volume. In short, Diskeeper orders data on the disk so that the content you use most often can be retrieved faster.

O&O Defrag
The installation of O&O Defrag proceeded without a hitch. One interesting feature of the installation routine is its Register O&O Defrag as the standard defrag tool check box. By contrast, PerfectDisk doesn’t replace the default, built-in defragmentation tool that comes with Windows, and Diskeeper replaces it without asking. O&O Defrag gives you a choice.

After installation, O&O Defrag immediately started a wizard to help set up OneButtonDefrag (which Figure 2 shows), a feature that promised to “automate defragmentation with just a few mouse clicks.” Opening the other products, I felt unsure where to begin; O&O Defrag got me started quickly on the right foot. I chose to use the wizard, selected Server (from a choice between Desktop, Laptop, or Server), and then File Server (from a choice between File Server, Database Server, Web Server, or Mail Server).

Next, I used the Check for Updates tool in the Help ribbon. The version I’d installed was the most up-to-date version, but this was a great feature that the competing vendors in this category would do well to consider.

Defragmenting. For online defrags, O&O Defrag uses a technology called ActivityGuard that monitors your CPU usage. When you’re performing CPU-intensive activities during a scheduled defrag, O&O Defrag uses less of your CPU. But when the processor is idle, O&O Defrag takes the opportunity to optimize more files. You can further tone ActivityGuard to use all available resources or a percentage of the CPU that you specify. In addition, you can set O&O Defrag to defrag each physical drive simultaneously or sequentially. You might choose simultaneous defrags if you need to quickly defrag all of a server’s disks. Defragging sequentially takes more time but saves valuable system resources.

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