Backup to Amazon S3 failing

Having the following error, assuming it's not Amazon that full so is it an issue that I need to have a certain amount of spare space on the local filesystem?

Backup failed! See the progress output above for the reason why. Total backup time was 17 minutes, 27 seconds.

Virtual servers that failed : ext.cleverfinance.com.au Sent by Virtualmin at: https://ns2:52525

Creating backup for virtual server ext.cleverfinance.com.au .. Copying virtual server configuration .. .. done

Backing up Cron jobs ..
.. none defined.

Copying records in DNS domain ..
.. done

Saving mail aliases ..
.. done

Saving mail and FTP users ..
.. done

Backing up mail and FTP user Cron jobs ..
.. none to backup

Copying Apache virtual host configuration ..
.. done

Copying Apache log files ..
.. done

Copying Webalizer configuration files ..
.. done

Copying SSL Apache virtual host configuration and certificate ..
.. done

Dumping MySQL database ext ..
.. done

Dumping MySQL database docs ..
.. done

Dumping MySQL database ext_limesurvey ..
.. done

Backing up AWstats configuration file ..
.. done

Creating TAR file of home directory ..
.. TAR failed! cat: write error: No space left on device

gzip: stdout: Broken pipe /bin/tar: -: Cannot write: Broken pipe /bin/tar: Error is not recoverable: exiting now