IBM Support

Reducing or removing paths for a multipath LUN



This document contains information on how to deconfigure or reduce the number of multipath paths in IBM i.

Resolving The Problem

This document contains information on how to unconfigure Multipath.

To unconfigure or reduce the number of paths configured to external storage, do the following:
1. Change the configuration on the ESS/Shark/DSxxxx to remove the extra port(s).
2. Physically remove the redundant fiber cable(s), if required.
3. IPL the server so the failed (removed) paths will change from failed status to non-reporting status during DASD discovery.
4. Run the Advanced Analysis command MULTIPATHRESETTER -RESETMP -ALL to set the number of expected paths to the actual number currently reporting:
a. On the operating system command line, run the STRSST command.
b. Select Option 1, Start a service tool, and press the Enter key.
c. Select Option 4, Display/Alter/Dump, and press the Enter key.
d. Select Option 1, Display/Alter storage, and press the Enter key.
e. Select Option 2, Licensed Internal Code (LIC) data, and press the Enter key.
f. Select Option 14, Advanced analysis (scroll down to see this option), and press the Enter key.
g. At the Select Advanced Analysis Command screen, scroll down, type 1 by MULTIPATHRESETTER, and press the Enter key.
h. At the Specify Advanced Analysis Options screen, type -RESETMP -ALL and press the Enter key.
i. Read and follow the instructions displayed on the screen to confirm that the paths should be reset.
1. If all redundant paths are removed, the disk resource names continue to appear as DMPxxx rather than DDxxxx.
2. Resources (DMPxxx) left behind in Hardware Service Manager for any removed paths will need to be cleaned up manually.
3. MULTIPATHRESETTER will not reset counts for failed paths, only non-reporting paths

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Modified date:
03 May 2023