Veritas Storage Foundation™ for Oracle 5.0.1 Administrator's Guide

Support for multi-volume file systems
The multi-volume file system (MVS) feature allows several volumes to be
represented by a single logical object. All I/O to and from an underlying logical
volume is directed by way of volume sets. A volume set is a container for multiple
different volumes. This feature can be used only in conjunction with Veritas
Volume Manager.
Support for large file systems and large files (optional)
Support for large file systems is included with the Enterprise Edition.
In conjunction with VxVM, VxFS can support file systems up to two terabytes in
size.
For large database configurations, this eliminates the need to use multiple file
systems because of the size limitations of the underlying physical devices.
Changes implemented starting with the VxFS Version 3 disk layout have greatly
expanded file system scalability, including support for large files.
You can create or mount file systems with or without large files by specifying
either the largefiles or nolargefiles option in mkfs or mount commands.
See “Creating a VxFS file system ” on page 56.
About Storage Checkpoints and Storage Rollback
The Storage Checkpoint and Storage Rollback features are included with the
Enterprise Edition. With the Standard Edition, they can be purchased as part of
the Veritas FlashSnap option.
Veritas File System provides a Storage Checkpoint facility that allows you to create
a persistent, point-in-time image of all user files in a file system—the Storage
Checkpoint remains even after the file system is unmounted or the system is
rebooted. Storage Checkpoints present a view of a file system at a point in time,
and subsequently identifies and maintains copies of the original file system blocks.
Instead of using a disk-based mirroring method, Storage Checkpoints save disk
space and significantly reduce I/O overhead by using the free space pool available
to a file system.
The time required to create a Storage Checkpoint is typically only a couple of
seconds. After a Storage Checkpoint is created, a consistent database backup
image is made and the database can then resume its normal operation.
The Storage Rollback facility can then be used for rolling back the file system
image to the point in time when the Storage Checkpoints were taken. In addition,
35Introducing Veritas Storage Foundation for Oracle
How Veritas File System works