When performing disk administration, it is important to understand the difference between a disk name and a device name.
When a disk is placed under VxVM control, a VM disk is assigned to it. You can define a symbolic disk name (also known as a disk media name) to refer to a VM disk for the purposes of administration. A disk name can be up to 31 characters long. If you do not assign a disk name, it defaults to diskgroup## where diskgroup is the name of the disk group to which the disk is being added, and ## is a sequence number. Your system may use device names that differ from those given in the examples.
The device name (sometimes referred to as devname or disk access name) defines the name of a disk device as it is known to the operating system. Such devices are usually, but not always, located in the
/dev/rdsk directories. Devices that are specific to hardware from certain vendors may use their own path name conventions.
VxVM recreates disk devices, including those from the
/dev/rdsk directories, as metadevices in the
/dev/vx/[r]dmp directories. The Dynamic Multipathing (DMP) feature of VxVM uses these metadevices (or DMP nodes) to represent disks that can be accessed by more than one physical path, usually via different controllers. The number of access paths that are available depends on whether the disk is a single disk, or is part of a multiported disk array that is connected to a system.
You can use the
vxdisk utility to display the paths subsumed by a metadevice, and to display the status of each path (for example, whether it is enabled or disabled).
See "Administering Dynamic Multipathing" on page 137.
Device names may also be remapped as enclosure-based names.
See "Disk device naming in VxVM" on page 82.