Caching and Data Recovery

The cache is the area of RAM that contains data. When you write data to disk, the lazy-write technique in Windows 2000 indicates that the data is written when, in fact, it is still in the cache. There can also be cache memory on the disk controller or on the disk itself. The following information will help you decide whether you want to enable the disk or controller cache:

• Turning on write caching improves disk performance, particularly if the disk is being heavily written to.
• Control of the write-back cache is a firmware function provided by the disk manufacturer. See the documentation supplied with the disk or disk controller. You cannot configure the write-back cache from Windows 2000.
• Write caching does not impact the reliability of the file system's own metadata. NTFS instructs the disk device driver to ensure that metadata writes get written regardless of whether write caching is enabled. Non-metadata is written to the disk normally, so such data can be cached.
• Read caching in the disk has no impact on file system reliability.

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