The best way to understand the condition of the link below the SM is to take a look at screen capture below. Unfortunately, we do not capture history of this statistic but it is supported via SNMP and you could poll it periodically to create history.
Thank you Sakid. With a big number of clients, pulling each one isn't a good choice. Sometimes you even can't see disconnections because they are very fast, when the cable is damaged.
An history of ethernet status and port speed could really help to diagnose this issue from remote!