Why few LUNs from the storage are not usable while other LUNs from the same storage are available ?

Issue

• Few of the LUNs from the storage are unusable while other LUNs from the same storage can be used. Unusable LUNs are available in the /proc/scsi/scsi though. Following error messages could be seen for the unusable LUNs.

Oct  8 17:02:44 localhost kernel: qla2300 0000:03:01.0: scsi(1:0:0:63): Enabled tagged queuing, queue depth 32.
Oct  8 17:03:00 localhost hal.hotplug[17459]: timout(10000 ms) waiting for /devices/pci0000:00/0000:00:0b.0/0000:03:01.0/host1/target1:0:0/1:0:0:63 
Oct  8 17:03:10 localhost scsi.agent[17462]: Attribute /sys/devices/pci0000:00/0000:00:0b.0/0000:03:01.0/host1/target1:0:0/1:0:0:63/type does not exist
Oct  8 17:04:25 localhost kernel: sdax: Spinning up disk.......................................................................................................not responding...
Oct  8 17:04:25 localhost kernel: sdax : READ CAPACITY failed.
Oct  8 17:04:25 localhost kernel: sdax : status=1, message=00, host=0, driver=08 
Oct  8 17:04:25 localhost kernel: Current sd: sense key Not Ready
Oct  8 17:04:25 localhost kernel: Additional sense: Logical unit not ready, cause not reportable
Oct  8 17:04:25 localhost kernel: sdax: asking for cache data failed
Oct  8 17:04:25 localhost kernel: sdax: assuming drive cache: write through
Oct  8 17:04:35 localhost multipathd: sdax: failed to store path info