Unable to mount iSCSI devices during boot process

Issue

• The system has iSCSI device managed by dm-multipath. It has ext4 filesystem and an entry for this device is added to /etc/fstab file, but it is unable to mount during boot process:

  $ cat /etc/fstab
  [...]
  /dev/mapper/3600123456789123456789123456789 /data ext4 defaults 0 0
  

  During boot process, the mount operation gets timed out with following errors:

  systemd[1]: dev-mapper-3600123456789123456789123456789.device: Job dev-mapper-3600123456789123456789123456789.device/start timed out.
  systemd[1]: Timed out waiting for device dev-mapper-3600123456789123456789123456789.device.
  systemd[1]: Dependency failed for /data.
  systemd[1]: Dependency failed for Remote File Systems.
  systemd[1]: remote-fs.target: Job remote-fs.target/start failed with result 'dependency'.
  systemd[1]: data.mount: Job data.mount/start failed with result 'dependency'.
  systemd[1]: dev-mapper-3600123456789123456789123456789.device: Job dev-mapper-3600123456789123456789123456789.device/start failed with result 'timeout'.
  [...]