Signal when galaxy_data mount is nearly full on logs

[pcm32]

Recently had an instance full due to the mount point serving /opt/galaxy_data was full. Error was quite cryptic and didn't lead easily to the disk full issue, so it might be good to print that out to the logs (disk status).

[sneumann]

Maybe as simple as http://m.linuxjournal.com/content/tech-tip-send-email-alert-when-your-disk-space-gets-low And use the email issued when provisioning. Yours Steffen --- I blame Android for the brevity and typos