Storage Partitioning - Dell PowerVault MD3260i Administrator's Manual

Operating System
Windows Server 2003 and Windows Server 2008
Linux
Guidelines when you work with host types with LUN mapping restrictions:
• You cannot change a host adapter port to a restricted host type if there are already mappings in the storage
partition that would exceed the limit imposed by the restricted host type.
• Consider the case of the Default Group that has access to LUNs up to 256 (0 to 255) and a restricted host type is
added to the Default Group. In this case, the host that is associated with the restricted host type is able to
access virtual disks in the Default Group with LUNs within its limits. For example, if the Default Group had two
virtual disks mapped to LUNs 254 and 255, the host with the restricted host type would not be able to access
those two virtual disks.
• If the Default Group has a restricted host type assigned and the storage partitions are disabled, you can map
only a total of 32 LUNs. Any additional virtual disks that are created are put in the Unidentified Mappings area. If
additional mappings are defined for one of these Unidentified Mappings, the Define Additional Mapping dialog
shows the LUN list, and the Add button is unavailable.
• Do not configure dual mappings on a Windows host.
• If there is a host with a restricted host type that is part of a specific storage partition, all of the hosts in that
storage partition are limited to the maximum number of LUNs allowed by the restricted host type.
• You cannot move a host with a restricted host type into a storage partition that already has LUNs mapped that
are greater than what is allowed by the restricted host type. For example, if you have a restricted host type that
allows only LUNs up to 31, you cannot move that restricted host type into a storage partition that has LUNs
greater than 31 already mapped.
The Default Group on the Host Mappings tab has a default host type. To change the host type, right-click on the host and
select Change Default Host Operating System from the pop-up menu. If you set the default host type to a host type that is
restricted, the maximum number of LUNs allowed in the Default Group for any host is restricted to the limit imposed by
the restricted host type. If a particular host with a non-restricted host type becomes part of a specific storage partition,
you are able to change the mapping to a higher LUN.

Storage Partitioning

A storage partition is a logical entity consisting of one or more virtual disks that can be accessed by a single host or
shared among hosts that are part of a host group. The first time you map a virtual disk to a specific host or host group, a
storage partition is created. Subsequent virtual disk mappings to that host or host group do not create another storage
partition.
One storage partition is sufficient if:
• Only one attached host accesses all of the virtual disks in the storage array
• All attached hosts share access to all of the virtual disks in the storage array
When you choose this type of configuration, all of the hosts must have the same operating system and special software
(such as clustering software) to manage virtual disk sharing and accessibility.
More than one storage partition is required if:
• Specific hosts must access specific virtual disks in the storage array
• Hosts with different operating systems are attached to the same storage array. In this case, a storage partition
is created for each host type
Highest LUN
255
255
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