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July 11, 2008
• Vol.30 Issue 28
Page(s) 27 in print issue
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Reclaiming Resources
Diskeeper Aims To Defrag Storage & Boost Performance With Its Offerings
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 Remember the defragmentation utility that you ran once a month or so on your IBM PC to clean up its 100MB hard drive? Do you still have a defragger on your PC today? Or use it? Increasingly, PCs are not only shipped with defrag utilities, but the corporate data center staff is making sure they are put to use.
“90% of the performance problems are due to fragmentation issues,” says Craig Jensen, CEO of Diskeeper (www.diskeeper.com), which makes automated defragmentation software for both corporate and home computer users.
In fact, a survey released by Diskeeper in June polled 179 network administrators on what software they felt was important to have on their servers. Of those polled, 45% named defragmentation software, with 61% of those citing performance as the key benefit of defragmentation.
 Fighting Fragmentation
Fragmentation occurs when data is stored in various pieces that are scattered around the available storage space rather than together in one contiguous block. When new files are stored, the computer distributes them across the available chunks of free space, and when a file is spread out over several locations, it takes longer to read and write. Besides slow performance, fragmentation can also result in longer boot times, crashes, and freezes.
“Users often blame the software or hardware, but often it’s the result of fragmentation,” says Jensen, who founded Diskeeper Corp. in 1981, originally under the name Executive Software. Its first defragmentation product helped land the company on Inc. magazine’s list of 500 Fastest-Growing Privately Held Companies in America for four years in a row. Originally designed for Digital Equipment’s VAX mainframe computers, it later moved to the Windows platform. Diskeeper then created a version just for Microsoft, which is included in most versions of Windows.
Defragmentation software rearranges stored data into more contiguous blocks, reducing fragmentation and also freeing up more storage space. Defragmentation utilities have been around for decades but have gradually lost popularity as computer networks have become larger and storage cheaper. Performance problems were often dealt with by adding more disk capacity.
“Data center managers have not always treated fragmentation as a major problem,” says Jensen. But he believes that corporate America is starting to take defragmentation seriously again.
Changing IT Trends Drive Changes In Defragmentation
Defragmentation is actually more critical today because of the heavier overhead that computer systems carry due to greater storage capacity, the pervasive use of video and graphics, and the increased use of antivirus and antispam software, says Jensen.
IT administrators must also deal with greater numbers of desktops, often remotely, which they did not have to worry about in the early days of defragmentation. Back in the 1980s and early ’90s, it was possible to manually defrag individual desktops. Today’s IT manager rarely has time to manually defrag dozens or hundreds of desktops scattered around the office or over the network.
Jensen says that and other changes in IT usage have also driven change in defragmentation software. For example, to accommodate the growth of remote PCs, Diskeeper 2008 has added administrative features so that an IT manager can configure and push Diskeeper out to networked PCs, as well as monitor them via a central desktop. To cope with the ever-increasing size of storage drives, it also now has a Terabyte Volume Engine for handling high-capacity drives more efficiently.
Virtualization is also exacerbating fragmentation: Because virtualization decouples the software logic from the physical hardware, fragmentation can occur in the physical drive and in the virtual storage, says Jensen.
“Some people think that because a system is virtualized, they can throw out all of the best practices of defragmentation,” says Jensen. “But a virtualized system suffers from three times the fragmentation. There’s fragmentation of the host [physical] system, and fragmentation of the guest, and fragmentation of the mapping of the relationship between the virtual disk and physical disk.”
Yet another issue is the advent of solid-state disks, which don’t have any moving mechanical parts. While presumed to be free from fragmentation worries, Jensen says they have actually proven to be more prone to fragmentation problems.
“Fragmentation has a bigger impact on a solid-state drive than on a rotating-disk drive. In one SSD we tested, we rated 100,000 free space fragments accumulated in less than eight weeks,” he says.
It’s the huge increase in storage media itself that has presented the greatest challenge, however.
“Storage just keeps growing and growing in size, so it’s been a big challenge keeping up with this explosion in capacity,” says Jensen. “Our R&D areas have to stay on top of how you defragment a multiterabyte drive—and defragment that drive in less than a production day.”
Changing Perceptions
Many IT managers have been reluctant to invest in defragging software because of its image as a time-consuming utility that takes over the computer. Because disks and servers have grown in size, thus requiring even more time to defragment, traditional defragging software often does have to run after hours. To keep up with the growth in storage and the faster pace of IT operations, Diskeeper has added InvisiTasking, a proprietary technology aimed at making defragmentation more invisible to the user.
InvisiTasking carefully schedules the sharing of computer resources between Diskeeper and other applications, enabling the Diskeeper defragmenter to operate without interrupting other programs.
“Normally, software programs share computer time on a round-robin basis, with each process getting the whole machine for a few milliseconds. But often, [a] program only needs the CPU but not the memory, or the disk but not the CPU. So we came up with a way to schedule programs that just need disk resources along with those that don’t need disk resources,” he explains. “So, Diskeeper can run without anyone being able to tell that it’s running.”
The InvisiTasking feature will be included in a future version of the company’s Undelete file recovery product, as well, and Jensen says he’s in the process of talking to hardware vendors about possible OEM deals.
“That’s probably the most exciting of the products we have,” says Jensen, pointing to backup processes and antivirus scanning as two applications that could benefit greatly from InvisiTasking. “Some backups are running 20 hours or longer. By reducing the overhead on that, a backup can be done during the production day. InvisiTasking is definitely [something] we will be focusing on more in the future.” 
by Sue Hildreth
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