Chapter 3 Functions of NEC Storage PathManager
specified integer.
C:\>spscmd -getlun
*** LogicalUnit #0 ***
> 0: Priority=2, PathNumber=4:0:0:0
1: Priority=1, PathNumber=5:0:1:0
C:\>spscmd -priority 5:0:1:0 3
C:\>spscmd -getlun
*** LogicalUnit #0 ***
0: Priority=2, PathNumber=4:0:0:0
> 1: Priority=3, PathNumber=5:0:1:0
C:\>
Priority specified in the -priority option must be an in teger between 1 and 254, and each path
must have a unique priority in a logical unit. Multiple numbers of the same priority cannot exist in a
logical unit. When specifying a priority, paths that are not displayed due to failures must be taken into
consideration. When a path with a particular priority recovers from failures and the same priority
already exists in the same logical unit, the priority of the path that has failed back will be changed (refer
to "4.1.2 Initial settings").
As described above, the -priority option must be used with much caution. Unless it is absolutely
necessary, use the -path option or the -swap option instead.
3.3 Load bal
lancing
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This function distributes I/O loads to available paths that are managed by NEC Storage PathManager. In
NEC Storage PathManager, there are two types of load balancing: static load bal ancing and dynamic load
balancing. Each type of load balancing will be described below.
3.
.3.1 S
Static load balancing
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In this method, loads will be distributed through static distribution of paths by the logical units. As seen
in the figure below, loads will be distributed by separating paths that access logical unit 0 from paths that
access logical unit 1.
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