vmunix: 0/2/1/0/4/0: Device at device id 0xd3000 has disappeared from Name Server GPN_FT

 Operating System:  HP-UX / HP-UX B.11.11
Few days back one of our server started reporting following errors



uxpro13}[/root/home/afus10]$  cat -n /var/adm/syslog/syslog.log|grep -i 0/2/1/0/4/0
   431  Jul  2 20:42:31 uxpro13 vmunix: 0/2/1/0/4/0: Device at device id 0xd3000 has disappeared from Name Server GPN_FT
   437  Jul  2 20:42:31 uxpro13 vmunix: 0/2/1/0/4/0: Device at device id 0xd3200 has disappeared from Name Server GPN_FT
   483  Jul  2 20:42:34 uxpro13 vmunix: 0/2/1/0/4/0: Device at device id 0xd3100 has disappeared from Name Server GPN_FT
   507  Jul  2 20:42:36 uxpro13 vmunix: 0/2/1/0/4/0: Device at device id 0xd3300 has disappeared from Name Server GPN_FT
   531  Jul  2 21:03:14 uxpro13 vmunix: 0/2/1/0/4/0: Device at device id 0xd3000 is back in Name Server GPN_FT (FCP type)
   539  Jul  2 21:03:14 uxpro13 vmunix: 0/2/1/0/4/0: Device at device id 0xd3200 is back in Name Server GPN_FT (FCP type)
   619  Jul  2 21:03:15 uxpro13 vmunix: 0/2/1/0/4/0: D
   631  Jul  2 21:03:17 uxpro13 vmunix: 0/2/1/0/4/0: Device at device id 0xd3300 is back in Name Server GPN_FT (FCP type)
   663  Jul  2 21:22:36 uxpro13 vmunix: 0/2/1/0/4/0: Device at device id 0xd3000 has disappeared from Name Server GPN_FT
   669  Jul  2 21:22:36 uxpro13 vmunix: 0/2/1/0/4/0: Device at device id 0xd3100 has disappeared from Name Server GPN_FT
   675  Jul  2 21:22:36 uxpro13 vmunix: 0/2/1/0/4/0: Device at device id 0xd3200 has disappeared from Name Server GPN_FT
   681  Jul  2 21:22:36 uxpro13 vmunix: 0/2/1/0/4/0: Device at device id 0xd3300 has disappeared from Name Server GPN_FT

We were not sure about the reason for this error. There were no case reported from any connected devices and the hardware paths were referring towards host HBAs.
finally we decided to check with storage/SAN side and we started to trace the   device id mentioned in the error log. We managed to find the WWN of the connected device corresponding to the ID using this method.

48   4    0   0d3000   id  2G  Online  F-Port  10:00:00:e0:02:23:39:54 49   4    1   0d3100   id   2G Online  F-Port  10:00:00:e0:02:23:39:6b 50   4    2   0d3200   id   2G Online  F-Port  10:00:00:e0:02:23:3e:75 51   4    3   0d3300   id   2G Online  F-Port  10:00:00:e0:02:23:40:55     

All the device IDs mentioned in that error log were representing tape library interface managers.For some maintenance work hardware team rebooted the library on that date. Still the reason for this error was not clear, as there were no tape drives allocated to this server from that library.

Finally, We managed to find out the actual cause for this error.The reason behind this error was single initiator multiple targets(meaning single interface controller is zoned to multiple host including the host which reported this error).