10400424-002 04/2013
©2013 Overland Storage, Inc.
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SnapSAN S3000/S5000 Path Manager Linux User Guide
Round Robin Mode (RoundRobin)
The path to which each I/O request is issued is changed sequentially from the higher priority
path to the lower priority path. After an I/O request is issued to the lowest priority path, the
next request is issued to the highest priority path.
Least I/O Size Mode (LeastSectors)
The path to which each I/O request is issued is changed to the path whose total I/O size is
least.
Configuration File
PathManager can associate a device file with the LUN by using the configuration file
(/etc/sps.conf). After the start of operation, you can change the setting using mkdd command.
Creating the Configuration File
Configuration file is created automatically when the server starts at first after installation.
And when you execute mkdd command, the configuration file is also created if it doesn't
exist. To change the setting, change the configuration file and execute mkdd command.
When the configuration file is created automatically, PathManager driver detects the disk
arrays and assigns the device file for each disk array in order of detection. And PathManager
driver also detects the paths and sets priorities of paths to every device.
And PathManager sets load distribution mode based on the model of detected disk array
(*1). The load distribution is least I/O size mode (leastsectors) for the models that support a
dynamic load distribution, and static load distribution mode (lbstatic) for those that don't
support a dynamic one (*2).
The format of automatically created configuration file is different in each function version of
PathManager.
Format and Reference of automatically created configuration file
Function Version
Configuration File Format
4.4.2 or later
1.3
