Restricted Mappings

Many hosts are able to map up to 256 logical unit numbers (LUNs) (0 to 255) per storage partition. However, the maximum number of mappings differs because of operating system variables, failover driver issues, and potential data problems. The hosts listed in the table have these mapping restrictions.

If you try to map a virtual disk to a LUN that exceeds the restriction on these operating systems, the host is unable to access the virtual disk.

Operating System

Highest LUN

 

 

Windows Server 2003 and Windows server 2008

255

Linux

255

 

 

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.

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Configuration: Disk Groups and Virtual Disks

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Dell MD3220i, MD3200i owner manual Restricted Mappings, 132, Operating System Highest LUN

MD3200i, MD3220i specifications

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