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The size of today's hard drives boggles the mind. 40GB is the norm and disks ten times that size are emerging. Coupled with this surge in disk capacity is an explosion in file sizes. Ten years ago, the average drive contained mainly word documents, each a few KB in size. Now, multi-MB PowerPoints, MP3s and PDFs litter the hard drive.The problem is that drive I/O speed has not kept up the pace. As a result, it has developed into a serious bottleneck in system performance.
Consider the facts: Processor speeds are measured in billions of operations per second; memory is measured in millions of operations per second; yet disk speed remains pegged at hundreds of operations per second.This disparity is minimized as long as the drive's read/write head can just go to a single location on the disk and read off all the information. But the huge gulf in speed between a disk and the CPU/memory is a severe problem when the disk is badly fragmented. Instead of taking half a second to open, a badly fragmented text document can take half a minute, and graphics-laden PowerPoints much longer. Not all of the extra work, however, is readily noticeable to the end user. Even after the user sees the opening screen, the system can still be working in the background to assemble all the remaining pieces. File fragmentation not only lowers performance, it leads to a catalog of woes such as slower virus scans and backups, databases corruption and premature hardware failures.
In this white paper, we discuss how fragmentation affects today's larger hard drives and files sizes, what this does to the system as a whole, and how this crippling bottleneck can be eliminated automatically on every server, workstation and laptop in the enterprise using automated defragmentation software.
Computer Heal Thy Self
A good technician can keep any system running. A better one designs systems so he doesn't have to.While a Formula One race car needs mechanics on hand to tune it before each race, commercial automobile manufacturers build self-tuning engines that constantly monitor and adjust engine performance without a trip to the shop. The driver simply drives and doesn't have to worry about what is happening under the hood.
IT managers need the same types of systems to achieve any acceptable level of performance and sanity. There are too many devices running too many processes for anyone to directly observe and manage. Yet all systems must be kept, not just from breaking down, but operating at peak performance. Equipment manufacturers and software developers, therefore, are researching and developing self-healing systems:
- IBM has its "autonomic computing" initiative which aims to create self-configuring, self-managing, self-optimizing, self-protecting, self-healing systems
- High-end storage systems from Hitachi Data Systems and EMC Corporation report back to their manufacturers' support centers for repair or tweaking without customer intervention
- IBM, Microsoft and Sybase offer self-healing databases
- Desktop applications automatically check for and install the latest security patches or updates
- Windows adjusts its paging file size as needed to meet usage demands.
Disk drives also have some self-healing properties. For example, the firmware will detect bad sectors and block them off, something that once had to be done manually. But there is another vital area - file fragmentation - that needs to be continually monitored and repaired to keep equipment and applications operating at peak levels. And, as with other aspects of IT management, it only works well if it is done on an automated rather than a manual basis.
The Disk is the Performance Bottleneck
File fragmentation was originally a feature, not a bug. Digital Equipment Corporation (DEC) developed it as part of its RSX-11 operating system as a revolutionary means to handle lack of disk space. But much has changed in the thirty five years since the debut of the RSX-11. At that time, a typical hard disk boasted a capacity of 2.5MB, and the entire disk had a read time of four minutes.
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