The issue you describe is very similar to a problem that was fixed in the latest firmware. The issue was that after a period of uptime, 6 weeks or geater, the switch would stop learning mac addresses. This would cause all ports to light as the switch would be acting more as a hub. If you still notice the issue after upgrading, please let us know.
I haven't noticed the behavior you have described; I have 3 SG300-28 ports in my lab with 4 NSS3xx and I’m replicating large amounts of data between two NSS3xx. I have about 40-50 hosts connected. Can you give me a better idea on the amount of data on your backups so I can send through for testing and see if i can accomplish what your switches behavior. I’m currently running a 75 GB file backup to another NSS3xx right now for testing.
I ran 75 GB backup through my network no symptoms. Backup started 15:21 to 16:49 1hr28min later. Since you're having trouble please give Cisco Small Business Support center a call and open a support case. We can take a look at your configuration and assist. (1-866-606-1866)
No worries the Cisco Small Business Support Center is open 24/7 so please call at your next available time. When calling we need to have topology of your network, how you are planning on implementing these switches. We will take a look at your setting and verified or narrow down what is causing the switch to behavior as you are describing. Replication and testing has to be done first (trouble shooting) after we determine it's not a configuration or environmental issue we then can move your case up the chain.
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