Enhanced I/O Performance

VxFS provides enhanced I/O performance by applying an aggressive I/O clustering policy, integrating with VxVM, and allowing application specific parameters to be set on a per-file system basis.

Enhanced I/O Clustering

I/O clustering is a technique of grouping multiple I/O operations together for improved performance. 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.

VxVM Integration

VxFS interfaces with VxVM to determine the I/O characteristics of the underlying volume and perform I/O accordingly. VxFS also uses this information when using mkfs to perform proper allocation unit alignments for efficient I/O operations from the kernel.

As part of VxFS/VxVM integration, VxVM exports a set of I/O parameters to achieve better I/O performance. This interface can enhance performance for different volume configurations such as RAID-5, striped, and mirrored volumes. Full stripe writes are important in a RAID-5 volume for strong I/O performance. VxFS uses these parameters to issue appropriate I/O requests to VxVM.

Application-Specific Parameters

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

• Discovered Direct I/O

All sizes above this value would be performed as direct I/O.

• Maximum Direct I/O Size

This value defines the maximum size of a single direct I/O.

For a discussion on VxVM integration and performance benefits, refer to VxFS Performance: Creating, Mounting, and Tuning File Systems, Application Interface, and the vxtunefs(1M) and tunefstab(1M) manual pages.