Defragmentation: Panacea or Placebo?
Hard disk fragmentation got a close look from Storage Supersite readers last week as they weighed in on the value of defragmentation and optimization for drive performance and reliability.
I sparked the debate in a recent column exploring the reliability side of defragmentation based on a briefing on the subject by Executive Software International, the makers of the Diskeeper utility. The paper posited that Windows XP requires managers to become more diligent about fragmentation than previous releases. (See "Windows Defraggled" for more information.)
Here are a couple of the responses as well as another talking point from Executives essay:
"All defragmenting is going to do for you is make your data more retrievable from a hard drive crash," observed Carey Holzman, a computer-repair specialist based in Phoenix. "People will swear to you that their Windows XP with NTFS systems runs faster after defragmenting. ... If youre convinced your system runs faster after its defragmented or partitioned, or after waving a dead chicken over your head, who am I to tell you that youre wrong? "But if you dont notice any difference after running a defragmentation utility, youre not alone," Holzman continued. "I have yet to see any great difference in boot-up or operational speeds after using the commercial products or even the built-in XP defragmenter."
By my reckoning, Holzman sounded a bit cavalier about the one feature of defragmentation software he considered useful. Improving the performance of data recovery in case your hard drive is trashed can be a lifesaver, allowing you to pull off critical data files intact.
Greg Brewer, president and CEO of data-recovery developer Prosoft Engineering, agreed: Your data-recovery program might not care that a file was stored all together or scattered in pieces, but defragmentation will improve chances of recovering a file if a the drive is so far gone that a technician must intervene.
However, Brewer warned that defragmentation or optimization can interfere with the integrity of your data. "Sometimes people notice that theyve lost a few files and decide to go ahead and defragment their hard drivethats the worse thing they can do in that case," Brewer said. The missing files can be a sign of directory corruption, and optimizing will simply "scramble the files."
Still, defragmentation can improve the speed of backups, according to the Executive Software papera worthy goal in the data-reliability department. When files are fragmented, the pieces must be consolidated before the file can be written to the backup set and verified.
Although everyone seemed to have at least something good to say about defragmentation, readers questioned the value of optimization, defragmentations flip side.
Holzman broached an interesting concern about optimization: He wondered if the constant defragmenting and moving files for optimization purposes might actually cause more wear and tear on the drive than would be achieved by ignoring it. "I suppose moderation in all things applies, rather then choosing one extreme (defragmenting constantly) or the other extreme (never defragmenting)."
Meanwhile, another reader, a technical product manager at a hard drive vendor, offered a different perspective on optimization. He said that while large storage systems may become fragmented, caches and look-ahead algorithms as well as routines in the operating system may mask most of the inefficiencies.
"It used to make a difference where data was stored on a disk," said the engineer, who declined attribution. "But with automatic bad-block error correction or remapping, track look-ahead caching, and transition from one surface to another, or RAID, you really dont know the physical-to-logical mapping that may exist on a storage system."
"Theres one thing that does work well and is more measurablemake sure your drive has plenty of free space," he added. "About the only thing that needs to be contiguous nowadays is swap disk space.
So heres the recap: The drive-optimization software company suggests you improve data reliability through defragmention; the computer tech suggests defragmentation to improve data-recovery times; and the drive vendor suggest most ills can be solved with a bigger drive. All seems right with the world.
David Morgenstern is a longtime reporter of the storage industry as well as a veteran of the dotcom boom in the storage-rich fields of professional content creation and digital video.