Veritas File System 5.1 SP1 Administrator"s Guide (5900-1499, April 2011)

and efficient backup strategies. Backup and restore applications can leverage a
Storage Checkpoint, a disk- and I/O-efficient copying technology for creating
periodic frozen images of a file system. 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.
Storage Checkpoint functionality is separately licensed.
See the Veritas Storage Foundation Advanced Features Administrator's Guide.
FileSnaps
A FileSnap is a space-optimized copy of a file in the same name space, stored in
the same file system. VxFS supports FileSnaps in the VxFS 5.1 SP1 release and
later, and on file systems with disk layout Version 8 and later.
See the Veritas Storage Foundation Advanced Features Administrator's Guide.
See the vxfilesnap(1) manual page.
Quotas
VxFS supports quotas, which allocate per-user quotas and limit the use of two
principal resources: files and data blocks. You can assign quotas for each of these
resources. Each quota consists of two limits for each resource: hard limit and soft
limit.
The hard limit represents an absolute limit on data blocks or files. A user can
never exceed the hard limit under any circumstances.
The soft limit is lower than the hard limit and can be exceeded for a limited amount
of time. This allows users to exceed limits temporarily as long as they fall under
those limits before the allotted time expires.
See “About quota limits” on page 77.
Support for databases
Databases are usually created on file systems to simplify backup, copying, and
moving tasks and are slower compared to databases on raw disks.
Using Quick I/O for Databases feature with VxFS lets systems retain the benefits
of having a database on a file system without sacrificing performance. Veritas
Quick I/O creates regular, preallocated files to use as character devices. Databases
can be created on the character devices to achieve the same performance as
databases created on raw disks.
25Introducing Veritas File System
Veritas File System features