Veritas Storage Foundation 5.1 SP1: Storage and Availability Management for Oracle (5900-1504, April 2011)

How Quick I/O works
Veritas Quick I/O supports direct I/O and kernel asynchronous I/O and allows
databases to access regular files on a VxFS file system as raw character devices.
The benefits of using Quick I/O are:
■ Improved performance and processing throughput by having Quick I/O files
act as raw devices.
■ Ability to manage Quick I/O files as regular files, which simplifies
administrative tasks such as allocating, moving, copying, resizing, and backing
up Oracle datafiles.
Note: Veritas recommends using Oracle Disk Manager.
See “Converting Quick I/O files to Oracle Disk Manager files” on page 69.
How Quick I/O improves database performance
Quick I/O's ability to access regular files as raw devices improves database
performance by:
■ Supporting asynchronous I/O
■ Supporting direct I/O
■ Avoiding kernel write locks on database files
■ Avoiding double buffering
About Oracle Disk Manager
Veritas Extension for Oracle Disk Manager enhances file management and disk
I/O throughput. The features of Oracle Disk Manager are optimized for Oracle
10g or later databases in a Veritas File System environment. Oracle Disk Manager
enables you to improve database throughput for I/O intensive workloads with
special I/O optimization.
Veritas Extension for Oracle Disk Manager supports Oracle Resilvering. With
Oracle Resilvering, the storage layer receives information from the Oracle database
as to which regions or blocks of a mirrored datafile to resync after a system crash.
Oracle Resilvering avoids overhead from the Volume Manager Dirty Region
Logging (DRL), which increases performance.
Oracle Disk Manager reduces administrative overhead by providing enhanced
support for Oracle Managed Files. Veritas Extension for Oracle Disk Manager has
57Overview of database accelerators
About Oracle Disk Manager