OceanStor Dorado5000 V3 LUN capacity fail to update on Oracle Enterprise Linux 7.2 after map changed.
1. Customer mapped one 195GB lun (wwn: 6e472e2100e8da7f139f66d100000015) originally.
2. Un-map the LUN022-DB on Devicemanager.
3. Create new 190GB lun and executed rescan command “echo "- - -" > /sys/class/scsi_host/hostX/scan”. But the capacity and also the wwn were not changed checked by command “multipathd -ll”.
Step 1 Confirm if the multipath is used.
Step 2 Confirm if the storage reported the lun. Key word is “ scsiReportLunsExecute”, such as: Report 69 LUN to host 0x10000090fae65d57,actual 69 LUN.][SCSI][scsiReportLunsExecute,458][CSD_5]
Multipath cannot update the disk information like capacity and wwn after map view is changed.
Solution A: clear the residual disk on host. Note: its high risky operation. If wrong disk deleted the service and data will impact. this solution refer to http://www.linuxquestions.org/questions/linux-distributions-5/finding-luns-928777/
1. deleted mpath device with “multipath -f mpath<number>”, in this case the command is “multipath -f mpathm”
2. delete the all hard disks by command “echo 1 > /sys/block/sdxxx/device/delete”, in this case the command is as following:
echo 1 > /sys/block/sdw/device/delete
echo 1 > /sys/block/sdx/device/delete
3. rescan by command “echo “- - -” > /sys/class/scsi_host/hostx/scan”, in this case the command is as following since there is only 2 initiator:
echo “- - -” > /sys/class/scsi_host/host0/scan
echo “- - -” > /sys/class/scsi_host/host1/scan
Use command “multipathd -ll” to check if the wwn and capacity are updated after the operation. Application scope is OceanStor V3/V5 serious storage.