Server Administrator Storage Management 8.2 User’s Guide

The Direct I/O and Cache I/O policy apply to readings on a specific virtual disk. These settings do not affect the read-ahead policy. The cache policies are:

• Cache I/O — Specifies that all reads are buffered in cache memory.
• Direct I/O — Specifies that reads are not buffered in cache memory. When using Direct I/O, data is transferred to the controller cache and the host system simultaneously during a read request. If a subsequent read request requires data from the same data block, it can be read directly from the controller cache. The Direct I/O setting does not override the cache policy settings. Direct I/O is the default setting.