Veritas Storage Foundation™ for Oracle 5.0.1 Administrator's Guide

How Veritas Extension for Oracle Disk Manager works
Veritas Extension for Oracle Disk Manager is a custom storage interface defined
by Oracle Corporation first introduced in Oracle9. Oracle Disk Manager allows
Oracle9 and above to exploit system bandwidth through an improved Application
Programming Interface (API) that contains advanced kernel support for file I/O.
Oracle Disk Manager reduces administration overhead by providing enhanced
support for the Oracle Managed Files (OMF) infrastructure also introduced
beginning with Oracle9. Combining Veritas Extension for Oracle Disk Manager
with Oracle9 offers better database throughput for I/O intensive workloads due
to specialized I/O features that greatly improve the I/O system call profile for
such key Oracle server processes as the Log Writer and Database Writers.
With Veritas Extension for Oracle Disk Manager, Oracle9 or Oracle 10 is able to
use the same system calls for datafiles stored in the Veritas File System as they
do with raw partitions. Oracle Disk Manager files look just like ordinary file system
files and can be handled as such. Care is given within Oracle Disk Manager to
ensure files are created with contiguous disk blocks automatically for improved
sequential file access performance. Oracle Disk Manager files can be backed up
and recovered through Veritas NetBackup, Oracle Recovery Manager (RMAN), or
other backup software.
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 require resynchronization
after a system crash. When using Oracle Resilvering, you can turn off VxVM Dirty
Region Logging (DRL), which increases performance.
Oracle Resilvering is supported at the operating system and application levels.
How Database Dynamic Storage Tiering works
Today, more and more data needs to be retained. Eventually, some of the data is
no longer needed as frequently, but it still takes up a large amount of disk space.
Database Dynamic Storage Tiering matches data storage with the data's usage
requirements so that data is relocated based on requirements determined by the
database administrator (DBA). The feature enables you to manage your data so
that less-frequently used data can be moved to slower, less expensive disks,
allowing frequently-accessed data to be stored on the faster disks for quicker
retrieval.
The DBA can create a file allocation policy based on filename extension before
new files are created, which will create the datafiles on the appropriate tier during
database creation.
39Introducing Veritas Storage Foundation for Oracle
How Veritas Extension for Oracle Disk Manager works