Veritas Storage Foundation™ for Oracle 5.0.1 Administrator's Guide

See the Veritas File System Administrator's Guide.

About Veritas Quick I/O

Databases can run on either file systems or raw devices. Database administrators

often create their databases on file systems because it makes common

administrative tasks (such as moving, copying, and backing up) easier. However,

running databases on most file systems significantly reduces database

performance.

When performance is an issue, database administrators create their databases

on raw devices. VxFS with Quick I/O presents regular, preallocated files as raw

character devices to the application. Using Quick I/O, you can enjoy the

management advantages of databases created on file systems and achieve the

same performance as databases created on raw devices.

Quick I/O can be used on Oracle9 and Oracle 10. If you are using Oracle9 or Oracle

10, it is recommended that you use Oracle Disk Manager.

See “About Quick I/O” on page 75.

About Veritas Cached Quick I/O

Cached Quick I/O allows databases to make more efficient use of large system

memory while still maintaining the performance benefits of Quick I/O. Cached

Quick I/O provides an efficient, selective buffering mechanism to back

asynchronous I/O. Using Cached Quick I/O, you can enjoy all the benefits of Quick

I/O and achieve even better performance.

Cached Quick I/O is first enabled for the file system and then enabled on a per file

basis.

See “About Cached Quick I/O” on page 101.

About Veritas Concurrent I/O

Veritas Concurrent I/O improves the performance of regular files on a VxFS file

system without the need for extending namespaces and presenting the files as

devices. This simplifies administrative tasks and allows databases, which do not

have a sequential read/write requirement, to access files concurrently.

Veritas Concurrent I/O allows for concurrency between a single writer and multiple

readers or between multiple writers. It minimizes serialization for extending

writes and sends I/O requests directly to file systems.

See “About Concurrent I/O” on page 115.

Introducing Veritas Storage Foundation for Oracle

How Veritas File System works