Why do my backup fail when I target a network share hosted by a Synology DS211 disk station?

Question

My backups are failing when I try to use a network share hosted by a Synology DS211 disk station. They work fine if I target a different network share (i.e. \server1\data\larry).

When I run the following command:

Wbadmin start backup -backupTarget:\\diskstation\backup-larry -include:C:

This is what I get:

wbadmin 1.0 - Backup command-line tool
(C) Copyright 2004 Microsoft Corp.


Note: The backed up data cannot be securely protected at this destination.
Backups stored on a remote shared folder might be accessible by other
people on the network. You should only save your backups to a location
where you trust the other users who have access to the location or on a
network that has additional security precautions in place.

Retrieving volume information...
This will back up volume WIN7(C:) to \\diskstation\backup-larry.
Do you want to start the backup operation?
[Y] Yes [N] No y

Note:  The list of volumes included for backup does not include all the
volumes that contain operating system components. This backup cannot be used
to perform a system recovery. However, you can recover other items if the
destination media type supports it.

The backup operation to \\diskstation\backup-larry is starting.
Creating a shadow copy of the volumes specified for backup...
Creating a shadow copy of the volumes specified for backup...
The backup operation stopped before completing.
Summary of the backup operation:
------------------

The backup operation stopped before completing.
Detailed error: Access is denied.
Windows Backup failed to write the file: '<backup location>\WindowsImageBackup\<Computer Name>\MediaId'.
Access is denied.

The backup creates the following path \\diskstation\backup-larry\WindowsImageBackup\LARRY-MYDOMAIN\ but its empty.

I definitely have read/write access on the target directory (\diskstation\backup-larry). I have verified this by looking at the permission and by actually copying files to this location.

Any suggestions?

Solution

I created an iSCSI target and used that for my backups. I'm still not sure why my original approach did not work.

Comments

[Larry]

Thanks for the suggestions so far. I'm certain that Wbadmin is running as the correct user. I've tried passing my credentials on the the command line and I've tried other locations that only I have access to. Both work if the network share is not on the the Synology disk station.