Dell MD3200, MD3220 owner manual Restricted Mappings, 126, Operating System Highest LUN

7If a new LUN is mapped or volume capacity is changed, run the following command:

#rescan_dm_devs

8Use the multipath -llcommand to verify that:

•If a new LUN is mapped, the new LUN is detected and given a multi- pathing device node

•If you increased volume capacity, the new capacity is displayed.

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

126

Configuration: Disk Groups and Virtual Disks