Veritas File System 5.0 Administrator's Guide (September 2006)

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 103.
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.
Treating regular VxFS files as raw devices has the following advantages for
databases:
■ Commercial database servers such as Oracle Server can issue kernel supported
asynchronous I/O calls (through the asyncdsk or Posix AIO interface) on these
pseudo devices but not on regular files.
See “About Quick I/O” on page 183.
Cluster file systems
Veritas Storage Foundation Cluster File System (SFCFS) allows clustered severs
to mount and use a file system simultaneously as if all applications using the file
system were running on the same server. The Veritas Volume Manager cluster
functionality (CVM) makes logical volumes and raw device applications accessile
through a cluster.
Beginning with SFCFS 5.0, SFCFS uses a symmetric architecture in which all nodes
in the cluster can simultaneously function as metadata severs. SFCFS still as some
remnants of the old master/slave or primary/secondary concept. The first server
to mount each cluster file system becomes its primary; all other nodes in the
cluster become secondaries. Applications access the user data in files directly
from the server on which they are running. Each SFCFS node has its own intent
log. File system operations, such as allocating or deleting files, can originate from
any node in the cluster.
Installing VxFS and enabling the cluster feature does not create a cluster file
system configuration. File system clustering requires other Veritas products to
21Introducing Veritas File System
Veritas File System features