Veritas Storage Foundation 5.1 SP1 Cluster File System Administrator"s Guide (5900-1738, April 2011)
file system block The fundamental minimum size of allocation in a file system. This is equivalent
to the fragment size on some UNIX file systems.
fileset A collection of files within a file system.
fixed extent size An extent attribute used to override the default allocation policy of the file system
and set all allocations for a file to a specific fixed size.
fragmentation The on-going process on an active file system in which the file system is spread
further and further along the disk, leaving unused gaps or fragments between
areas that are in use. This leads to degraded performance because the file system
has fewer options when assigning a file to an extent.
GB (gigabyte) 2
30
bytes or 1024 megabytes.
hard limit The hard limit is an absolute limit on system resources for individual users for
file and data block usage on a file system.
heartbeat Heartbeat messages are sent over the private link to obtain information on cluster
membership changes. If a node does not send a heartbeat for 16 seconds, it is
removed from the membership. The command lltconfig is used for information
on the various heartbeat parameters. The low latency transport (LLT) module
provides communication services across the cluster.
indirect address extent An extent that contains references to other extents, as opposed to file data itself.
A single indirect address extent references indirect data extents. A double indirect
address extent references single indirect address extents.
indirect data extent An extent that contains file data and is referenced via an indirect address extent.
inode A unique identifier for each file within a file system that contains the data and
metadata associated with that file.
inode allocation unit A group of consecutive blocks containing inode allocation information for a given
fileset. This information is in the form of a resource summary and a free inode
map.
intent logging A method of recording pending changes to the file system structure. These changes
are recorded in a circular intent log file.
internal quotas file VxFS maintains an internal quotas file for its internal usage. The internal quotas
file maintains counts of blocks and indices used by each user.
KB (kilobyte) 2
10
bytes or 1024 bytes.
large file A file larger than two terabytes. VxFS supports files up to 8 exabytes in size.
large file system A file system larger than two terabytes. VxFS supports file systems up to 8 exabytes
in size.
latency For file systems, this typically refers to the amount of time it takes a given file
system operation to return to the user.
203Glossary