Veritas Volume Manager (VxVM) uses multiple virtualization layers to provide distinct functionality and reduce physical limitations. The connection between physical objects and VxVM objects is made when you place a physical disk under VxVM control.
Table: VxVM virtual objects describes the virtual objects in VxVM.
Table: VxVM virtual objects
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Virtual object
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Description |
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Disk groups
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A disk group is a collection of disks that share a common configuration and which are managed by VxVM. A disk group configuration is a set of records with detailed information about related VxVM objects, their attributes, and their connections. A disk group name can be up to 31 characters long. Disk group names must not contain periods (.). |
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VxVM disks
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A VxVM disk is assigned to a physical disk, when you place the physical disk under VxVM control. A VxVM disk is usually in a disk group. VxVM allocates storage from a contiguous area of VxVM disk space.
Each VxVM disk corresponds to at least one physical disk or disk partition.
A VxVM disk typically includes a public region (allocated storage) and a small private region where VxVM internal configuration information is stored.
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Subdisks
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A subdisk is a set of contiguous disk blocks. A block is a unit of space on the disk. VxVM allocates disk space using subdisks. A VxVM disk can be divided into one or more subdisks. Each subdisk represents a specific portion of a VxVM disk, which is mapped to a specific region of a physical disk. |
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Plexes
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A plex consists of one or more subdisks located on one or more physical disks. |
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Volumes
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A volume is a virtual disk device that appears to applications, databases, and file systems like a physical disk device, but does not have the physical limitations of a physical disk device. A volume consists of one or more plexes, each holding a copy of the selected data in the volume. Due to its virtual nature, a volume is not restricted to a particular disk or a specific area of a disk. The configuration of a volume can be changed by using VxVM user interfaces. Configuration changes can be accomplished without causing disruption to applications or file systems that are using the volume. For example, a volume can be mirrored on separate disks or moved to use different disk storage. |
After installing VxVM on a host system, you must bring the contents of physical disks under VxVM control by collecting the VxVM disks into disk groups and allocating the disk group space to create logical volumes.
Bringing the contents of physical disks under VxVM control is accomplished only if VxVM takes control of the physical disks and the disk is not under control of another storage manager such as LVM.
For more information on how LVM and VxVM disks co-exist or how to convert LVM disks to VxVM disks, see the Veritas InfoScale Solutions Guide.
VxVM creates virtual objects and makes logical connections between the objects. The virtual objects are then used by VxVM to do storage management tasks.
The vxprint command displays detailed information about the VxVM objects that exist on a system.
See the vxprint(1M) manual page.
