VERITAS Volume Manager 3.5 Administrator's Guide (September 2002)

Chapter 1, Understanding VERITAS Volume Manager
Online Relayout
31
System administrators can manipulate the layered volume structure for troubleshooting
or other operations (for example, to place data on specific disks). Layered volumes are
used by VxVM to perform the following tasks and operations:
◆ Creating striped-mirrors. (See “Creating a Striped-Mirror Volume” on page 175, and
the vxassist(1M) manual page.)
◆ Creating concatenated-mirrors. (See “Creating a Concatenated-Mirror Volume” on
page 171, and the vxassist(1M) manual page.)
◆ Online Relayout. (See “Online Relayout” on page 31, and the vxrelayout(1M) and
vxassist(1M) manual pages.)
◆ RAID-5 subdisk moves. (See the vxsd(1M) manual page.)
◆ Snapshots. (See “Backing Up Volumes Online Using Snapshots” on page 214, and the
vxassist(1M) manual page.)
Note The VERITAS Enterprise Administrator (VEA) terms a striped-mirror as
Striped-Pro, and a concatenated-mirror as Concatenated-Pro.
Online Relayout
Note You may need an additional license to use this feature.
Online relayout allows you to convert between storage layouts in VxVM, with
uninterrupted data access. Typically, you would do this to change the redundancy or
performance characteristics of a volume. VxVM adds redundancy to storage either by
duplicating the data (mirroring) or by adding parity (RAID-5). Performance
characteristics of storage in VxVM can be changed by changing the striping parameters,
which are the number of columns and the stripe width.
See “Performing Online Relayout” on page 221 for details of how to perform online
relayout of volumes in VxVM. Also see “Converting Between Layered and Non-Layered
Volumes” onpage 224for informationaboutthe additional volumeconversion operations
that are possible.
How Online Relayout Works
Online relayout allowsyou to changethe storage layoutsthat you havealready created in
place without disturbing data access. You can change the performance characteristics of a
particular layout to suit your changed requirements. You can transform one layout to
another by invoking a single command.