This section provides solution to common problems users experience during online storage reconfiguration.
When a LUN is deleted on a configured filer, the change is not reflected on the host. In such cases, lvm commands will hang indefinitely when dm-multipath is used, as the LUN has now become stale.
To work around this, perform the following procedure:
Determine which mpath link entries in /etc/lvm/.cache are specific to the stale LUN. To do this, run the following command:
ls -l /dev/mpath | grep
<stale LUN>
For example, if <stale LUN>
lrwxrwxrwx 1 root root 7 Aug 2 10:33 /3600d0230003414f30000203a7bc41a00 -> ../dm-4 lrwxrwxrwx 1 root root 7 Aug 2 10:33 /3600d0230003414f30000203a7bc41a00p1 -> ../dm-5
This means that 3600d0230003414f30000203a7bc41a00 is mapped to two mpath links: dm-4 and dm-5.
Next, open /etc/lvm/.cache. Delete all lines containing <stale LUN>mpath links that <stale LUN>
Using the same example in the previous step, the lines you need to delete are:
/dev/dm-4 /dev/dm-5 /dev/mapper/3600d0230003414f30000203a7bc41a00 /dev/mapper/3600d0230003414f30000203a7bc41a00p1 /dev/mpath/3600d0230003414f30000203a7bc41a00 /dev/mpath/3600d0230003414f30000203a7bc41a00p1