VMware backup error: Error opening the snapshot disks using given transport mode: Status 23

Problem

VMware backup error: Error opening the snapshot disks using given transport mode: Status 23

Error Message

2013-7-17 0:14:18 - Error bpbrm (pid=27669) from client myclient: ERR - Error opening the snapshot disks using given transport mode: Status 23
2013-7-17 0:14:20 - Error bptm (pid=27677) media manager terminated by parent process
2013-7-17 0:14:25 - Info nbu5220 (pid=27677) StorageServer=PureDisk:nbu5220; Report=PDDO Stats for (nbu5220): scanned: 2 KB, CR sent: 0 KB, CR sent over FC: 0 KB, dedup: 100.0%
2013-7-17 0:14:25 - Info bpbkar (pid=0) done. status: 6: the backup failed to back up the requested files
2013-7-17 0:14:32 - Info nbjm (pid=8776) starting backup job (jobid=336) for client myclient, policy Lasa_VM_Backup, schedule Full
2013-7-17 0:14:32 - estimated 0 kbytes needed
2013-7-17 0:14:32 - Info nbjm (pid=8776) started backup (backupid=myclient_1373991272) job for client myclient, policy 
Lasa_VM_Backup, schedule Full on storage unit stu_disk_nbu5220
2013-7-17 0:14:33 - started process bpbrm (pid=27669)
2013-7-17 0:14:34 - connecting
2013-7-17 0:14:34 - connected; connect time: 0:00:00
2013-7-17 0:14:35 - begin writing
2013-7-17 0:14:48 - end writing; write time: 0:00:13
the backup failed to back up the requested files (6)

Cause

Similar messages may be seen in ...../netbackup/logs/vxms log on the VMware backup host:

07/19/2013 10:59:10 : vdConnect:VixInterface.cpp:869 <DEBUG> : Done with VixDiskLib_Connect(): 9301344
07/19/2013 10:59:10 : connectToHost:VixGuest.cpp:1112 <INFO> : ChangeTracking is disabled/unsupported
07/19/2013 10:59:10 : vdOpen:VixInterface.cpp:367 <INFO> : Calling VixDiskLib_Open()
07/19/2013 10:59:10 : g_vixInterfaceLogger:libvix.cpp:1829 <INFO> : VixDiskLib: Trying to open disk [lun_sata05] symantecHAtest/symantecHAtest.vmdk using mode nbd.
07/19/2013 10:59:10 : g_vixInterfaceLogger:libvix.cpp:1829 <INFO> : NBD_ClientOpen: attempting to create connection to vpxa-nfc://[lun_sata05] symantecHAtest/symantecHAtest.vmdk@netbackup.com:902
07/19/2013 10:59:10 : g_vixInterfaceLogger:libvix.cpp:1829 <INFO> : CnxAuthdConnect: Returning false because CnxAuthdConnectTCP failed
07/19/2013 10:59:10 : g_vixInterfaceLogger:libvix.cpp:1829 <INFO> : CnxConnectAuthd: Returning false because CnxAuthdConnect failed
07/19/2013 10:59:10 : g_vixInterfaceLogger:libvix.cpp:1829 <INFO> : Cnx_Connect: Returning false because CnxConnectAuthd failed
07/19/2013 10:59:10 : g_vixInterfaceLogger:libvix.cpp:1829 <INFO> : Cnx_Connect: Error message: Host address lookup for server netbackup.com failed: Temporary failure in name resolution
07/19/2013 10:59:10 : g_vixInterfaceLogger:libvix.cpp:1829 <INFO> : NBD_ClientOpen: Couldn't connect to netbackup.com:902 Host address lookup for server netbackup.com failed: Temporary failure in name resolution  
07/19/2013 10:59:10 : g_vixInterfaceLogger:libvix.cpp:1829 <INFO> : DISKLIB-DSCPTR: : "vpxa-nfc://[lun_sata05] symantecHAtest/symantecHAtest.vmdk@netbackup.com:902" : Failed to open NBD extent
07/19/2013 10:59:10 : g_vixInterfaceLogger:libvix.cpp:1829 <INFO> : DISKLIB-LINK  : "vpxa-nfc://[lun_sata05] symantecHAtest/symantecHAtest.vmdk@netbackup.com:902" : failed to open (NBD_ERR_NETWORK_CONNECT).  
07/19/2013 10:59:10 : g_vixInterfaceLogger:libvix.cpp:1829 <INFO> : DISKLIB-CHAIN : "vpxa-nfc://[lun_sata05] symantecHAtest/symantecHAtest.vmdk@netbackup.com:902" : failed to open (NBD_ERR_NETWORK_CONNECT)  
07/19/2013 10:59:10 : g_vixInterfaceLogger:libvix.cpp:1829 <INFO> : DISKLIB-LIB   : Failed to open 'vpxa-nfc://[lun_sata05] symantecHAtest/symantecHAtest.vmdk@netbackup.com:902' with flags 0x1e NBD_ERR_NETWORK_CONNECT (2338).
07/19/2013 10:59:10 : vdOpen:VixInterface.cpp:372 <DEBUG> : Done with VixDiskLib_Open(): 0
07/19/2013 10:59:10 : vdOpen:VixInterface.cpp:376 <ERROR> : VixDiskLib_Open() error: 13
07/19/2013 10:59:10 : openLeafSnapshotDisks:VixGuest.cpp:463 <ERROR> : vdOpen() error = 13. Calling closeLeafSnapshotDisks()
07/19/2013 10:59:10 : log:Error.cpp:305 <WARN> : Error: 0x00000017 occured in file VixGuest.cpp, at line 609
07/19/2013 10:59:10 : log:Error.cpp:305 <WARN> : Error: 0x00000017 occured in file VixGuest.cpp, at line 609
07/19/2013 10:59:10 : vixMapObjCtl:VixCoordinator.cpp:968 <ERROR> : Returning: 23

Solution

The VMware Backup host is using the short name for the virtual machine in its hosts file.

This particular issue was resolved by correcting the name resolution on the backup host, added the domain name "netbackup.com" as the alias to the hosts file.

Make sure the ESX server can be resolved by the VMware backup host.