What are the different possible values for the path_checker configuration option in /etc/multipath.conf?

This option sets which method multipathd uses to check whether a particular path (and device) is available:

• tur uses a specific SCSI command (TEST UNIT READY)

• readsector0 tries to read the first sector of the disk device

There is also emc_clariion and hp_sw, which are EMC and ...