Guide for S.M.A.R.T. data?

My 6 TB drives on DL2100 are getting a bit tired, I think. In the process of replacing with larger ones. In the meantime, I’m curious as to the meaning of the S.M.A.R.T data. Wondering if anyone with more experience could offer a bit of insight.
a)This unit is on RAID 1. The SMART data list for each drive is identical… Wondering why that is.
b)Actual data sample is as follows. Is the fact that the current value and the “worst” value are the same good or bad? values are Current/Worst/Threshold
*Raw Read Error Rate 200 / 200 / 51
*Spin Up Time 219 / 196 / 21
*Reallocated Sector Ct 200 / 200 / 0
*Offline Uncorrectable 100 / 253 / 0

Thanks for any help.


Please refer to the following KB article: Understanding S.M.A.R.T. and S.M.A.R.T. failure and errors