Chapter 3 Functions of NEC Storage PathManager
Chapter 3 Functions of NEC Storage PathManager This chapter describes functions that NEC Storage PathManager offers. Basic functions of NEC Storage PathManager
can be roughly categorized as follows:
/1/ Path state display
This function displays information regarding state of paths.
/2/ Path control
This function sets the state of paths.
/3/ Load balancing
This function distributes I/O loads to multiple paths.
/4/ Cluster liaison
This function enables the program to operate in a cluster environment (such as CLUSTERPRO and
MSCS).
/5/ Path patrol
This function monitors the state of paths. It also detects failures and recovery from failur es as they occur.
/6/ Failure avoidance and failure recovery
This function shuts down failed paths when failures occur, uses the failover function to use alternative
paths, and uses the failback function at the time of failure recovery.
/7/ Log extraction
This function outputs operation information and failure information to system log files and de dicated log
files as operation histories.
/8/ Message (ESMPRO liaison)
This function issues notifications to operators as performance or failure information is outputted.
3.1 Path state display
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The path state display function is the most basic function of NEC Storage PathManager. For each logical
unit, this function lists the state of the paths that are managed by NEC Storage PathManage r.
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An spscmd will activate the path state display function. The state of the paths managed by NEC Storage
PathManager will first be described below. Then corresponding spscmd options such as the -getlun option
used in path state display will be described.