Disk Defragmenters for Microsoft Servers
Windows is very effective at writing non-contiguous blocks of files. As the euphemism states, this is a feature: You want to be able to use disk space effectively by writing to the first available free cluster. Newer files rapidly become fragmented when you erase and rewrite. As the disk becomes full, this fragmentation becomes significant enough to affect performance and system reliability. Less fragmentation also makes the task of data recovery easier.
In 1981, Executive created the first online commercial defragmenter for DEC’s OpenVMS. Executive also wrote the move file API that Microsoft uses to allow defragmentation and the Windows-included defragmenter. Unlike other products reviewed here, Executive doesn’t believe that file placement makes a performance difference, based on National Software Testing Labs (NSTL) studies, so it does not order files. Diskeeper does offer very flexible scheduling, and with the optional administration pack, it also monitors disk free space, a significant problem in most environments. In my test environment, resource usage was limited and fluctuated according to the tasks that were running. The choices for priority under “Change your settings” relate to how aggressively Diskeeper will hold on to resources if other processes need them. The default is the lowest priority. (See Figure 1.) Diskeeper suggests 15 percent to 20 percent free space, but ran well with 6 percent free space. This is in contrast to what other products claim in competitive analysis. See www.execsoft.com.
Figure 1: Winternal’s Defrag Manager
Raxco’s PerfectDisk installed very quickly and was among the fastest at completing the initial pass. Utilization varied sinusoidally over time. PerfectDisk works for both workstation and server, and no other version is required for TB arrays. You may also change what is considered a recently used file and determine if free space should be aggressively consolidated. (See www.raxco.com.)
O&O Defrag, though it uses more CPU time, has the most options for ordering files. With AD, you may send defragment schedules and jobs to clients, and the O&O GUI makes using saved schedules a matter of one click. Uniquely, O&O senses when laptops are battery powered and will defer defragmenting until plugged in. See www.oo-software.com.
Other defragmenters displayed a wealth of disk information and colorful fragment maps, but Winternals adapts a minimalist approach, showing simultaneous pre- and post-analysis. (See Figure 2.) Defrag Manager is designed for network use. Once a schedule is created, clicking on other machines adds them to the task, and no client is used when jobs are run remotely. Defrag Manager was one of the fastest defragmenters, but also displayed the highest CPU utilization. See www.winternals.com.
Figure 2: Executive’s Diskeeper
Your choice should be based on features, price and philosophy. Any choice from the products covered here will work well. For additional information on defragmenting, read “Defragmenters for Non-Microsoft Systems” online at www.certmag.com/networktools/defragment.
Doug Mechaber is a network engineer and architect who enjoys finding new ways to make his work easier. Douglas has written for Network Computing and remains active in several local user groups. He now works as an independent consultant. Send him the names of your favorite utilities at email@example.com.