Veritas File System 5.0 Release Notes, HP-UX 11i v3, First Edition, May 2008

NOTE: Concurrent I/O is not included in Base-VxFS or OnlineJFS. Additional licenses are
required.
• Nested mount support
This feature allows mounting of a VxFS file system on any of the VxFS mount points. A
directory on a shared VxFS file system can be used as a mount point for a VxFS file system,
enabling nested mounts of shared file systems.
NOTE: To enable nested mount support an additional license is required. The nested
mounts cannot be enabled with Base-VxFS and HP OnlineJFS. See Table 1-3 for the products
that bundle this license.
• Multi-volume file system availability
The multi-volume file system support enables a VxFS file system to span several VxVM
volumes. MVFS availability allows you to mount a multi-volume file system even if the
component data-only volume is missing or becomes unavailable. Any I/O error on a data-only
volume will not affect access to non-data-only volumes. In addition, all VxFS operations
that do not access the missing data-only volumes will function normally. This helps guarantee
the availability of some volumes even when other volumes within the file system are not
available.
NOTE: To enable the Multi-Volume File System Support (MVFS) feature, an additional
license is required. The MVS feature is not supported with Base-VxFS and HP OnlineJFS.
See Table 1-3 for the products that bundle this license.
• Dynamic Storage Tiering
Dynamic Storage Tiering (DST) allows administrators of multi-volume VxFS file systems to
manage the placement of files on individual volumes in a volume set by defining placement
policies that control both initial file location and the circumstances under which existing
files are relocated.
DST was called Quality of Storage Service (QoSS) in 4.1 and has been significantly enhanced
in 5.0. It basically implements a storage service level differentiator for better optimization
of storage resources. It enables you to manage your data so that less-frequently used data
can be moved to slower, less expensive disks, and frequently-accessed data can be stored
on the faster disks for quicker retrieval.
Files are usually closely associated with business purpose: documents, tables of transaction
records, images, audio tracks, and other digital business objects are all conveniently
represented as files, each with a business value. Files are therefore obvious objects around
which to optimize storage and I/O cost and performance. The key to deriving value from
multiple tiers of storage is to place each file on the appropriate type of storage device. More
critical files should be placed on higher-performing, more reliable devices. Less critical files
can be placed on less costly ones.
Manually relocating millions of files between tiers of storage devices would be a never-ending
task. Automation is a necessity for utilizing multiple tiers of storage effectively, and the
more files an enterprise has, the more of a necessity it becomes.
10 Veritas File System 5.0 Release Notes