Veritas File System 4.1 Administrator's Guide (HP-UX 11i v3, February 2007)

Glossary
VxVM
Glossary 241
soft limit The soft limit is lower than a hard limit.
The soft limit can be exceeded for a limited time.
There are separate time limits for files and
blocks. See also hard limit and quota..
Storage Checkpoint A facility that provides a
consistent and stable view of a file system or
database image and keeps track of modified data
blocks since the last Storage Checkpoint.
structural fileset The files that define the structure
of the file system. These files are not visible or
accessible to the user.
super-block A block containing critical
information about the file system such as the file
system type, layout, and size. The VxFS
super-block is always located 8192 bytes from the
beginning of the file system and is 8192 bytes long.
synchronous writes A form of synchronous I/O
that writes the file data to disk, updates the inode
times, and writes the updated inode to disk. When
the write returns to the caller, both the data and the
inode have been written to disk.
T
TB Terabyte (240 bytes or 1024 gigabytes).
transaction Updates to the file system structure
that are grouped together to ensure they are all
completed
throughput For file systems, this typically refers to
the number of I/O operations in a given unit of
time.
U
Unbuffered I/O I/O that bypasses the kernel cache
to increase I/O performance. This is similar to
direct I/O, except when a file is extended; for direct
I/O, the inode is written to disk synchronously, for
unbuffered I/O, the inode update is delayed. See
also buffered I/O and direct I/O.
volume A virtual disk which represents an
addressable range of disk blocks used by
applications such as file systems or databases.
volume set A container for multiple different
volumes. Each volume can have its own geometry.
vxfs The VERITAS File System type. Used as a
parameter in some commands.
VxFS The VERITAS File System.
VxVM The VERITAS Volume Manager.