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:
The MVS APIs fall into the following basic categories: