Veritas Volume Manager 5.1 SP1 Administrator"s Guide (5900-1506, April 2011)

■ Initializing and starting a volume
■ Accessing a volume
■ Using rules and persistent attributes to make volume allocation more efficient
About volume creation
Volumes are logical devices that appear as physical disk partition devices to data
management systems. Volumes enhance recovery from hardware failure, data
availability, performance, and storage configuration.
Volumes are created to take advantage of the VxVM concept of virtual disks. A
file system can be placed on the volume to organize the disk space with files and
directories. In addition, you can configure applications such as databases to
organize data on volumes.
Disks and disk groups must be initialized and defined to VxVM before volumes
can be created from them.
See “About disk management” on page 78.
See “About disk groups” on page 208.
Types of volume layouts
VxVM allows you to create volumes with the following layout types:
A volume whose subdisks are arranged both sequentially and
contiguously within a plex. Concatenation allows a volume to be
created from multiple regions of one or more disks if there is not
enough space for an entire volume on a single region of a disk. If
a single LUN or disk is split into multiple subdisks, and each
subdisk belongs to a unique volume, this is called carving.
See “Concatenation, spanning, and carving” on page 36.
Concatenated
A volume with data spread evenly across multiple disks. Stripes
are equal-sized fragments that are allocated alternately and evenly
to the subdisks of a single plex. There must be at least two subdisks
in a striped plex, each of which must exist on a different disk.
Throughput increases with the number of disks across which a
plex is striped. Striping helps to balance I/O load in cases where
high traffic areas exist on certain subdisks.
See “Striping (RAID-0)” on page 38.
Striped
Creating volumes
About volume creation
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