Sharepoint GRT backup failed with error 13 & 42

[Dgo]

Hello All,

We have NBU 7.7.x Master and Media server(App 5230) setup. And we are backing up Sharepoint over LAN.

Backup is failling with err 13/42  (GRT bkp for Sharepoint). below are more logs  (already increased client read/connect timed out value)

Log1:

03/28/2016 09:50:32 - Error bpbrm (pid=219991) from clientxxx: ERR - Terminating backup.
03/28/2016 09:50:32 - Error bptm (pid=220146) system call failed - Connection reset by peer (at child.c.1307)
03/28/2016 09:50:32 - Error bpbrm (pid=219991) from client xxxx: ERR - failure reading file: Microsoft SharePoint Resources:\Microsoft SharePoint Foundation Web Application\xxx\Cxxxx\(Sql/DBx4/Wxx_Content_Ixxx)\WSS_Contentxxxxxcv (BEDS 0x0: )
03/28/2016 09:50:33 - Error bptm (pid=220146) unable to perform read from client socket, connection may have been broken
03/28/2016 09:50:34 - Error bptm (pid=220118) media manager terminated by parent process
03/28/2016 09:50:38 - Info xxxx (pid=220118) StorageServer=PureDisk:xxxx-nbu5230; Report=PDDO Stats (multi-threaded stream used) for xxx): scanned: 105963794 KB, CR sent: 7628590 KB, CR sent over FC: 0 KB, dedup: 92.8%, cache hits: 278 (3.6%), rebased: 57 (0.7%)
03/28/2016 09:50:40 - Error bpbrm (pid=219991) could not send server status message
03/28/2016 09:50:41 - Info bpbkar (pid=16768) done. status: 13: file read failed
03/28/2016 09:50:41 - end writing; write time: 0:46:50
file read failed  (13)

Anyone can suggest on this, plz.

[Dgo]

Also, recycled NFS on all sharepoint servers & sql servers (2 node cluster). But same error on next schedule run.

[Marianne]

Does backup succeed without GRT selection in policy? This will help to determine if issue is with GRT or something else. Snippets of job details do not help. All details are needed as well as logs such as bptm and bpbrm on the media server and bpbkar log on Sharepoint client.