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About 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.

About 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.

About 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.

  Note   VxFS does not operate on AIX Logical Volume Manager (LVM) volumes. You can convert LVM volumes to VxVM volumes for use by VxFS. See the Veritas Volume Manager Migration Guide for more information.

About 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.

See VxFS performance: creating, mounting, and tuning File Systems.

See the vxtunefs(1M) and tunefstab(4) manual pages.