Enhanced I/O Performance

VxFS provides enhanced I/O performance by applying an aggressive I/O clustering policy.

Enhanced I/O Clustering

I/O clustering is a technique of grouping multiple I/O operations together for improved performance. The VxFS I/O policies provide more aggressive clustering processes than other file systems and offer higher I/O throughput when using large files; the resulting performance is comparable to that provided by raw disk.

Application-Specific Parameters

System administrators can also set application specific parameters on a per-file system basis to improve I/O performance.

Default Indirect Extent Size
On disk layout Version 2, this value can be set up to apply to all the indirect extents, provided a fixed extent size is not already set and the file does not already have indirect extents. The Version 3 and 4 disk layout uses typed extents which have variable sized indirects.
Discovered Direct I/O
All sizes above this value would be performed as direct I/O.
NOTE: The Discovered Direct I/O parameter is available only with the HP OnLineJFS product.
Maximum Direct I/O Size
This value defines the maximum size of a single direct I/O.
NOTE: The Maximum Direct I/O Size parameter is available only with the HP OnLineJFS product.

For a discussion of performance benefits, refer to Chapter 5 “Performance and Tuning ”, Chapter 6 “Application Interface”, vxtunefs(1M), and tunefstab(4).

Enhanced I/O Performance

Technical documentation

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Enhanced I/O Clustering

Application-Specific Parameters