first down load megacli zip file
wget https://docs.broadcom.com/docs-and-downloads/sep/oracle/files/Linux_MegaCLI-8-07-07.zip
then unzip and install
unzip Linux_MegaCLI-8-07-07.zip
yum install MegaCli-8.07.07-1.noarch.rpm
Now run to see all Disks
/opt/MegaRAID/MegaCli/MegaCli64 -PDList -aALL