Unless you get a message that the RAID array is degraded ignore the SMART message if you can still access your data on the network. I say that because the bulk of the SMART parameters are non critical as far as the disk firmware is concerned so the drive continues working without problems. There are some parameters that are critical and cause the disk firmware to flag the drive as defective which causes the software RAID to flag the array as degraded and ask for a replacement drive to rebuild the array.
To find out exactly what the SMART status is (except projected failure times) you need a few tools.
First you need a USB/SATA adapter with an external power supply.
Next you need to download the disk manufacturers disk tools.
Then attach the drive to the adapter, install the disk tools on your computer, plug the adapter into a USB port and run the disk tools against that port/drive. Work your way through the tools menu (be careful of anything that writes to the disk) and you will end up knowing more about your disk than you need to know.
If you look at the second screen grab I posted you will see that Attribute 9 is supposed to time out this month - the drive is still working without problems.