Cannot delete Mac Time Machine sparsebundles

We do support Mac backups and in 6.9.3 we added support for TM backups over SMB which is the preferred protocol to use for backups with recent versions of OS X. Samba the Linux project (used for the SMB protocol on Linux) recently added support for Time Machine. Prior to this we only supported TM backups over AFP.

I forgot that the NAS sees the sparsebundle as a directory containing lots of directories and files, not a single large file so the truncate a file method isn't for this. Deleting the backup normally would work but it will take a while.

I manually deleted your TM backups but there was one Mac that had a backup in progress so I couldn't successfully delete that backup.

To do it yourself is very straightforward

First you would disable TM backups on all the machines that have TM backups that you want to delete.

There is a KB article describing how to delete Time Machine backups: ReadyNAS: Removing Time Machine data

There's a method to delete TM backups using your web browser described in that KB article.

If you want to use SSH you'd do

# cd /data/.timemachine

Use ls to see the sparsebundles and do e.g.

# rm -rf *.sparsebundle

Be very careful entering the rm -rf command as that will try to delete everything you ask it to recursively and forcefully.

The MAN page for rm shows what the options do, -r is for recursive and -f is to force. As the sparsebundle contains a lot of directories and files this will take a while.

Note that using SSH is unsupported. If you break things we may be unable to provide help. 

Once all the TM backups have been deleted you would then make sure the appropriate TM quota(s) are set and then re-enable TM backups on the relevant Macs.

A last resort is to backup your data, do a factory reset (wipes all data, settings, everything) and restore your data from backup but you shouldn't need to resort to that for something like this.

Note you can backup your Mac to multiple different TM destinations. TM will rotate between backing up to the different available destinations.

Edit: Hmmm it looks like the web admin GUI option no longer works, but you can still use the AFP method or login to SMB as the admin user and go to smb://ip.address.of.nas/data/.timemachine (where data is the name of the volume) and delete the sparsebundles.