Last year (2017) I had to exchange 1 of the 6 original 1To drives… they've worked 24/24 for 5 years.
As I got surprised, I exchanged the faulty drive #3 and I prefered to erase everething and make it complete new, using my backups. No problem… just a waste of time.
Now, I need to renew one by one the other 5 drives, because another old drive got a problem, last week.
It happened that this 4# drive failed (red light, alarm, declared dead) and disappeared… I stopped the machine.
After 2 minutes, it was possible to launch the complete R6 which awakened completely OK, even the 4# drive.
At this time, I have bought 2 new drives (1To each) to make the change of 4# and keep a new one for another time.
I asked myself to grow from 1To to 2To drives, but I'm perfect with 5To usable in Raid5 and I'm conscious that my Pegasus R6 (2012-mod1) has done the half of its life (more is a gift !).
I can't read technical terms fluently (I'm French) … so I'd like to read your advices to operate the exchange of each drive, each month a new one, allowing to reconstruct the array.
Thanks for your advices,