Veritas™ File System 5.0.1 Programmer's Reference Guide

Multi-volume support

This chapter includes the following topics:

■ About multi-volume support

■ Uses for multi-volume support

■ Volume application programming interfaces

■ Allocation policy application programming interfaces

■ Data structures

■ Using policies and application programming interfaces

About multi-volume support

The multi-volume support (MVS) feature lets a VxFS file system use multiple

VxVM volumes as underlying storage instead of the traditional single volume per

file system. These different volumes can have different characteristics, such as

performance, redundancy, or cost, or they could be used to isolate different parts

of the file system from each other for performance or administrative purposes.

Administrators and applications can control which files and metadata go into

which volumes by using allocation policies. Each file system operation that

allocates space examines the applicable allocation policies to see which volumes

are specified for that operation. Allocation policies normally only affect new

allocations, but there are also interfaces to move existing data to match a new

allocation policy.

The following levels of policies can apply to each allocation:

■ Per-file policies

■ Per-Storage-Checkpoint policies

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