V-79-57344-65072 – The connection to target system has been lost. Backup set canceled.
I ran into this error recently at one of my clients with their new Backup Exec 2012 implementation. The jobs would sometimes work, but mostly they would fail with the error above. They would also fail at seemingly random byte counts. The implementation was backing up two servers. One of the servers was also the media server and this local backup always succeeded as expected and without incident. The other server, the one that was often failing, was the one with the remote agent.
This made me quickly look towards the network. As a test, I kicked off the problematic backup and monitored the network bandwidth usage in Task Manager on both servers. I also had a continuous ping going between the two servers. The first thing that became apparent was that the network bandwidth (100Mb switch) was completely saturated during the backup. Both servers continually reported a steady hold at 100% network utilization.
Then it happened. At first, I saw the continuous ping start to fail between the two servers. Then I noticed the network links as being reported down on both servers. I could only assume at this point the switch that connected these two servers together was having problems. I logged into the switch and checked the uptime. Lo and behold the switches uptime was just a couple of minutes. I repeated this test a few more times and even tried different switch ports and network cables. Same result every time. The switch kept rebooting. I could only assume this older switch could not handle the constant 100% network load.
As a temporary workaround, I knew both servers had a secondary unused network port. We created a new non-routable IP subnet using the secondary network ports and a small 5-port 1GB switch. We then redirected the Backup Exec job to send all data over this new network. We kicked off another job and it was successful. To this date, I have been running this way for about 1 month now without a single failure.
I hope this helps anyone else experiencing intermittent connection issues with Backup Exec Remote Agents.