You better be very very sure which drive is bad. I honestly couldn't tell which drive was bad from the log that you posted. I guess the easiest thing to do is check out the troubleshooting section of the Administrators guide, regarding "repairing a degraded array" on page 157 onwards. I have a link to the manual below.
But be careful, If you remove the wrong drive, you will destroy the raided volume. Much to my shame I did that once to my NSS4100, but i was very lucky, i had a backup copy of the data to restore. Check the NSS4000 GUI management screen to see if you can really identify the cause of the degraded array or the RAID tab , may show you which drive is 'not in array'.
If you are still unsure you always have the opportunity to call the SBSC. Their contact details can be obtained from the following URL;
Time Machine Backup on NSS300 Smart Storage Series
This document explains the steps for Time Machine Backup. The Network Attached Storage (NAS) is used as one of the destinations for the backup of files. It is a file-level ...
Basic and Advanced System Reset on NSS300 Series Smart Storage
The NSS devices have two types of System Resets: Basic and Advanced. An understanding of both of these resets will allow the user to recover from unpredictable si...
Expansion of Disk Capacity of RAID 5 on the NSS300 Series (Except NSS322)
RAID stands for Redundant Array of Independent Disks. RAID 5 combines three or more disks in a way that shields the data against loss of any one disk. ...