VERITAS Volume Manager 3.1 Migration Guide

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Glossary
block A unit of space for data on a disk, typically having a size of
1024-bytes.
Dirty Region Logging Dirty Region Logging (DRL) is an optional
property of a volume, used to provide a speedy recovery of mirrored
volumes after a system failure. DRL keeps track of the regions that have
changed due to I/O writes to a mirrored volume.
file system The organization of files on storage devices. The term file
system can refer either to the entire file system or to a subsection of that
file system, contained within a disk section or a logical volume that can
be mounted or unmounted from that tree.
logical volume A logical structure that is a map of storage areas on
physical volumes. A logical volume can be conceptualized as a storage
device of flexible size. The data in a logical volume can be mapped to one
or more physical volumes. A virtual disk device that represents a
contiguous virtual disk space that maps to single or multiple areas on a
single or multiple physical volumes.
LVM The Logical Volume Manager (LVM) is a subsystem for managing
disk space. LVM is an HP-UX product, similar to VxVM.
LIF The Logical Interchange Format (LIF) is a HP mass-storage format
that can be used for interchange of files among various HP computer
systems. Each boot disk has a LIF directory that contains boot programs.
logical Extent A set of logical blocks that maps to one physical extent
and is a basic unit of access in a logical volume.
MirrorDisk/UX HP-UX software product that allows disk mirroring as
part of LVM functionality. MirrorDisk/UX allows up 2 mirror copies in a
volume.
Mirror Write Cache (MWC) A MirrorDisk/UX mechanism whose use
is optional, that tracks outstanding mirror write requests and provides a
basis for the resynchronization of data blocks after a system crash.
physical volume A disk that has been initialized by LVM becomes
known as a physical volume.