Redhat Linux -Troubleshooting SAN Lun unavailability and HBA Issue

First , we will try to understand the Scenario  Suppose the LUN is coming from a storage and it is being used on Redhat Linux in LVM. Now when you run df -k, you see errors.

#df -k - This gives an error on the filesystem

Run pvs  -This will give us the details of the disk.
Look at the left column of PV, this will give you the details disks present in the volume group vgora

#pvs

  PV              VG     Fmt  Attr PSize   PFree
  /dev/emcpoweray vgora  lvm2 a--  101.15G    0
  /dev/emcpowerx1 vgora  lvm2 a--  139.70G 9.70G
  /dev/sda2       vgroot lvm2 a--   31.97G    0

Check the details of the HBA

a. HBA Port state

root@test1: # cat /sys/class/fc_host/host1/port_state

Online

b. HBA speed 

root@test1: # cat /sys/class/fc_host/host1/speed

4 Gbit

c.Port Name -WWPN

root@test1: # cat /sys/class/fc_host/host1/port_name

0x20010024e859e129

d.Node Name -WWNN

root@test1: # cat /sys/class/fc_host/host1/node_name

0x20000024e859e129

Provide the required info to the Storage team and they may help you to resolve the problem.