If you have an ndmp node there is a guide on how to use that with a cifs share. 

Otherwise you could map it to a file server and run a backup that has the option in the dataset to 'Traverse fixed-disk and remote network mounts'

I have run a manual backup to a UNC path before using the 'enter one File, Folder, or Directory' option in the 'Select for Backup' window of the 'Backp and Restore' window in MCS.

Make sure the account that is running the Avamar agent on the server has access to the remote location though - we had to run it with a domain account.  It is slower than a normal backup though.

Did all according https://community.emc.com/thread/99248?start=15&tstart=0

But somehow it won't work.

It's been a while since I ran one but I think I ended up having to run the backup manually from the 'Backup Restore' window rather than on a schedule with a dataset.  Try entering the UNC path into the 'Enter one File, Folder, or Directory' option for running an on-demand backup to test if that will work.

I am trying that CIFS share backup too from workgroup NAS.

I have tried several things according https://community.emc.com/thread/99248?start=15&tstart=0

DATASET

SOURCE

(a) Windows File System

(b) path for the CIFS like \\"IP ADDRESS"\shared folder

Clicked OK

"traverse fixed and remote network mounts" is selected.

Agent service is running workgroup user that has all access to NAS folders.

Logged in to computer where Avamar client is running with that username and password I have access to the NAS's folders.

Backup runs and when browsing backup from the restore-application it only shows folders but no files at all.

Backups used space is correct.

Earlier with another NAS I managed to get this CIFS share work making pre and after scripts that mounts NAS folders and datasets source was those mapped drives.

Now I can not make it work with this nas and I would like to use this UNC-paths.

Errors in log are:

error:getSIDname:LookupAccoutSidW, LastError=1332

I think this error is because those file privileges won't come from network source.

avtar error <5737>: I/O error: Unable to read (3) "\\ipaddress\folder\file" (code 50: ...)

filestream:readfilenext error: "\\ipaddress\folder\file" aborting cycle.

Can someone help me because I think that I am close to get this work?