Chapter 4 Operating NEC Storage PathManager
/3/ For an already recognized path to an already recognized logical unit, the state of priority will be
maintained even after the system is rebooted.
/4/ When a path is already recognized as a path to an already recognized logical unit, and is recovered from
path failures, the path will have a priority level that it had prior to the failures. Whether the priority is
disabled or enabled will depend on the failback mode. When a path having a certain priority is recovered
from failures, and a different path having the same priority exists in the same logical unit, then the priority
will be determined in accordance with /2/ above.
To summarize, if a newly found path is the first path found in a logical unit, its priority becomes 1 and
enabled. As other paths are found after that in the logical unit, they will be sequentially allocated with
priority that goes up by 1 for each path. Their prioritie s will be disabled. Once priority is allocated, after
the system is rebooted the same priority will be allocated unless changes are made. The following image
shows an example of path state immediately after installation of NEC Storage PathManager.
C:\>spscmd -getlun
*** LogicalUnit #0 ***
> 0: Priority=1, PathNumber=4:0:0:0
@ 1: Priority=2, PathNumber=5:0:1:0
@ 2: Priority=3, PathNumber=6:0:2:0
@ 3: Priority=4, PathNumber=7:0:3:0
*** LogicalUnit #1 ***
> 0: Priority=1, PathNumber=4:0:0:1
@ 1: Priority=2, PathNumber=5:0:1:1
@ 2: Priority=3, PathNumber=6:0:2:1
@ 3: Priority=4, PathNumber=7:0:3:1
C:\>
As seen in the image, only the path that is found first is enabled in each logical unit immediately after
installation of NEC Storage PathManager. NEC Storage PathManager can operate as it is; however, it is
recommended that all paths be enabled and settings for priority be made as necessary before starting
operation unless there is a special reason not to do so.
IV-4