How to figure out the problem RAIDа?

Help figure out the problem.
This system has the health information:
Problem:
0 RAID Adapter(LSI MegaRAID 2108) - Slot 6 is
CRITICAL
at 2016-05-15 22:58:02
Detailed:
0 RAID Adapter(LSI MegaRAID 2108) - Slot 6(558.911 GB) needs attention; Port Status is Active, 2 is Media Error, Other Error is 0, Predictive Failure is 0 Last Predictive Failure Number is 0, Firmware State is online

this means? what can I do?