VERITAS Volume Manager 3.5 User's Guide - VERITAS Enterprise Administrator (June 2002)

Chapter 4, Volume Tasks 81
VxVM Volumes
Mirrored
- Mirroring provides protection
against disk failure and reduces
the risk of data loss.
- Mirroring provides data
redundancy by maintaining
multiple complete copies of
volume data on different disks.
- Mirroring provides improved
read performance.
- A mirrored volume requires extra
disk space. Each mirror requires
enough disk space to contain a
complete copy of the volume.
Concatenated Pro
- The volume is layered, and
concatenates several underlying
mirror volumes. This provides
improved data redundancy and
reduces the impact of disk
failures. This type of volume is
also known as a
concatenated-mirror volume.
- Recovery time is quicker than
with regular concatenated
volumes that are mirrored.
- The volume can consist of disk
regions that are not adjacent.
- The volume can span multiple
disks. A spanned volume can
have a greater capacity than a
single disk.
- A concatenated pro volume
requires at least two disks.
- Concatenation does not improve
I/O performance.
- Layered volumes consist of more
VxVM objects than non-layered
volumes and are likely to fill upthe
disk group configuration database
sooner. When the configuration
database is full, you cannot create
more volumes in the disk group.
Striped Pro
- The volume is layered, and
stripes several underlying
mirror volumes. This provides
improved data redundancy and
reduces the impact of disk
failures. This type of volume is
also known as a striped-mirror
volume.
- Recovery time is quicker than
with regular striped volumes
that are mirrored.
- Striping provides improved
read and write performance.
- Striping can help to balance the
I/O load from multi-user
applications across multiple
disks.
- A striped pro volume requires at
least four disks.
- Layered volumes consist of more
VxVM objects than non-layered
volumes and are likely to fill upthe
disk group configuration database
sooner. When the configuration
database is full, you cannot create
more volumes in the disk group.
Layout Comparison
Layout Advantages Disadvantages