Dell PowerVault MD3220 - Manual (Page 51)

Planning: MD3200 Series Storage Array Terms and Concepts 51
Host Server-to-Virtual Disk Mapping
The host server attached to a storage array accesses various virtual disks on
the storage array through its host ports. Specific virtual disk-to-LUN
mappings to an individual host server can be defined. In addition, the host
server can be part of a host group that shares access to one or more virtual
disks.
You can manually configure a host server-to-virtual disk mapping. When you
configure host server-to-virtual disk mapping, consider these guidelines:
• You can define one host server-to-virtual disk mapping for each virtual disk
in the storage array.
• Host server-to-virtual disk mappings are shared between RAID controller
modules in the storage array.
• A unique LUN must be used by a host group or host server to access a
virtual disk.
• Not every operating system has the same number of LUNs available for
use.
Host Types
A host server is a server that accesses a storage array. Host servers are mapped
to the virtual disks. Host servers have the following attributes:
• Host name—A name that uniquely identifies the host server.
• Host group (used in Cluster solutions only)—Two or more host servers
associated together to share access to the same virtual disks.
This host group is a logical entity you can create in MDSM. All host servers
in a host group must be running the same operating system.
• Host type—The operating system running on the host server.
Snapshot Virtual Disks
A snapshot is a point-in-time image of a virtual disk. The snapshot provides
an image of the virtual disk at the time the snapshot was created. You create a
snapshot so that an application (for example, a backup application) can
access the snapshot and read the data while the source virtual disk remains
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