NAS Slow, Reboot Slow, Drive Light Blinking

I would have also opted to replace Drive 6, if it were an option.  However, Drive 2 was the one blinking incessently, and even though it had fewer errors, it was apparently the squeakiest wheel today.  Further, the reboot NEVER finished.  It hung at 94% for over 90 minutes. 

I finally gave up on the reboot and powered down the ReadyNAS entirely a second time, replaced Drive 2, and rebooted.  As advertised, it booted up in about 5 minutes, detected the degraded array, and immediately started the Rebuild Process.  The system is now working substantially better, and even with the RAID rebuild running, it is turning out better performance than I was getting all this week.  I can now send that drive back to WD, get the replacement, and then swap out drive 6 later on.  (Strangely, drive 6 was the only drive that had been replaced once before.  When the new drive 6 was put in, drive 6 started spewing errors after about a week.  This makes me wonder if there is not a problem with the SATA controller or cabling, and that perhaps drive 6 is really OK.)

Lessons learned:

1) Don't assume that the system is working properly, just becasue the Web console shows all drives are green.

2) Don't assume that the drive with the most errors is the one with the biggest problem. 

3) Ignore the data in the logs and just replace the drive that is blinking out of sync with everyone else.

4) Always have at least one spare drive on standby.