有关系统性能优化技巧

歆然6458

　　磁盘I/O性能优化
　　Tune Disk Performance
　　
　　Windows磁盘性能优化技巧：
　　下面的文字从微软的技术资料库中而来：
　　Some disk tuning suggestions from the article - "if your disk system is too slow, consider the following alternative steps:
- Rule out a memory shortage. When memory is scarce, the Virtual Memory Manager writes more pages to disk, resulting in increased disk activity. Because low memory is a common cause of bottlenecks, make surethat this is not the source of the problem before adding hardware. Also, make sure to set the paging file to an appropriate size as described in "Evaluating Memory and Cache Usage" in this book.
- Defragment the disk using Disk Defragmenter. For information about using Disk Defragmenter, see Windows 2003/2008 Help.
- Use Diskpar.exe on the Windows 2003/2008 Resource Kit companion CD to reduce performance loss due to misaligned disk tracks and sectors.
- Use striped volumes to process I/O requests concurrently over multiple disks. The type you use depends on your data-integrity requirements. Implement striped volumes for fast reading and writing and improvedstorage capacity. When striped volumes are used, disk utilization per disk need to fall due to distribution of work across the volumes and overall throughput need to increase. When using striped volumes, make sure to use the optimal size of stripe for yourworkload. The stripe size needs to be a multiple of the size of the average request. If you find that there is no increased throughput when scaling to additional disks in a striped volume, you might be experiencing a bottleneck due to contention between disksfor the disk adapter. You might need to add an adapter to better distribute the load.
- Place multiple drives on separate I/O buses, particularly if a disk has an I/O-intensive workload.
- Distribute workload among multiple drives. For example, for database applications, you might want to put transaction logs on a separate spindle from data. Notice that writing to a log file is a sequentialoperation and tends to be more efficient than the random operations typical of accessing data in a database. If you are unsure of a suitable distribution for network applications, track users and the files they work with in order to plan an efficient distributionby means of the auditing capability of the NTFS file system. This tells you which disks are getting the most usage and helps you determine whether you need to redistribute workloads. For more information about auditing, see Windows 2003/2008 Professional Help.
- Limit your use of file compression or encryption. These features can add some overhead and you need to use them sparingly if not required by your enterprise and if performance is critical.
- When obtaining disk systems, use the most intelligent and efficient components available for your disk system, including controller, I/O bus, cabling, and the disk. Upgrade to faster-speed or wider-bandwidthcomponents as necessary. These measures generally decrease transfer time and improve throughput. Use intelligent drivers that support interrupt moderation or interrupt avoidance to alleviate the interrupt activity for the processor due to disk I/O. Some graphscan be used for the disk monitoring page for clarity.
　　
　　用中文解释叙述如下：
1. 规避内存短缺问题，因为当操作系统的内存不够之时，必将引发虚拟内存（pagefile)的大量操作，从而导致系统的整体性能大幅下降；
2. 磁盘碎片整理，当磁盘的碎片大量存在时，因为搜索寻址的时间大幅延长从而导致整体的性能大幅下降，适当的时候进行碎片整理是非常有必要的；
3. 使用磁盘的条带卷来并行在多个磁盘之间进行I/O并行化处理，从而大幅提升磁盘的I/O性能；
4. 在不同的I/O总线上放置多个磁盘来提升并行速度；
5. 将磁盘的读写负载分散到多个磁盘上；
6. 在应用系统上限制使用文件压缩以及加密功能，避免过多增加磁盘的随机读写操作；
7. 升级你的磁盘控制器、I/O总线、数据线以及磁盘的数据读写速度，从而大幅提高磁盘I/O性能；
　　
　　
　　推荐一个整体性能优化专题网站：http://www.performancewiki.com/， 里面有各种各样的优化主题，涵盖应用、数据库、操作系统等等。