RHEL: Scan and configure new SAN (fibre channel) LUNs |
# Tested on RHEL 5 & 6
# Identify host adapters on the system systool -c fc_host Class = "fc_host" Class Device = "host3" Device = "host3" Class Device = "host4" Device = "host4" ls /sys/class/fc_host host3 host4 # Rescan the hbas # ------------------------------------------------------------------------------------------ echo "- - -" > /sys/class/scsi_host/host3/scan echo "- - -" > /sys/class/scsi_host/host4/scan # If this commands don't get to make new LUNs visible to system, you can try a "issue_lip"
# rescan. # Take into account that rescanning via "issue_lip" will reset the HBAs what may cause # a data loss if I/O operations are going on. Use this type of scan only when necessary. # In addition, as per Red Hat recommendations, the following restrictions must be observed # when scanning storage interconnects: # # All I/O on the effected interconnects must be paused and flushed before executing the # procedure, and the results of the scan checked before I/O is resumed. # # As with removing a device, interconnect scanning is not recommended when the system is # under memory pressure. To determine the level of memory pressure, run the command # "vmstat 1 100"; interconnect scanning is not recommended if free memory is less than 5% # of the total memory in more than 10 samples per 100. It is also not recommended if # swapping is active (non-zero 'si' and 'so' columns in the "vmstat" output). The command # "free" can also display the total memory. # I recommend to use "issue_lip" rescan only in case of servers that are discovering fibre # SAN disk for first time: # echo "1" > /sys/class/fc_host/host3/issue_lip # echo "1" > /sys/class/fc_host/host4/issue_lip |
Posted - Sun, May 27, 2018 8:29 PM. This article has been viewed 7445 times. |
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