Restricted Mappings - Dell POWERVAULT MD3600F Owner's Manual

# echo 1 > /sys/block/sd_x/device/delete
where sd_x is the SD node (disk device) returned by the multipath
command. Repeat this command for all paths related to this device.
For example:
#echo 1 > /sys/block/sdf/device/delete
#echo 1 > /sys/block/sde/device/delete
5 Remove mapping from MDSM, or delete the LUN if necessary.
6 If you want to map another LUN or increase volume capacity, perform this
action from MDSM.
NOTE:
7 If a new LUN is mapped or volume capacity is changed, run the following
command:
# rescan_dm_devs
8 Use the multipath -ll command 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 9-3 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.
Table 9-3. Mapping Restrictions
Operating System
Windows Server 2003 and Windows server 2008
Linux
Guidelines when you work with host types with LUN mapping restrictions:
132
Configuration: Disk Groups and Virtual Disks
If you are only testing LUN removal, you can stop at this step.
Highest LUN
255
255