Answer
Two options for upgrading based on network connectivity:
If your AMP can reach the internet, then you can use the automated method:
# start_amp_upgrade -v 7.6.4
This will then prompt you for your support account username and password.
If your AMP can't reach the internet directly, you can use the manual method:
1. Login to support.arubanetworks.com
2. Download AirWave upgrade package from Download -> AirWave -> AMP -> current version -> 7.6.4
3. Upload into /root (WinSCP is a common tool used for transferring from Windows to AMP)
4. Initialize the upgrade
# start_amp_upgrade -v 7.6.4
Additional tips from community members:
1. Key point, before initializing the upgrade, change directories to /root so you're not in the directory getting upgraded.
Also, if you're upgrading over ssh, run screen first so a disconnected session won't break everything.
2. We had an upgrade issue one time, and we were advised to clear the RRD cache prior to the upgrade.
I don't know that it is neccesary everytime, but I usually clear the RRD cache prior to the upgrade. It's become like rubbing the rabbit's foot.
Clearing the RRD cache
# rm -rf /var/airwave/cache/rrdcached/rrd.journal*
# rm -rf /var/lib/airwave/cache/fastmmap/awrrdtool_write_cache
# service rrdcached restart