Have a HP ML 350G6 with a P410i Raid controller and 3 x 146 GB hotswap SAS drives.
One is defect.
Have swap theese drives many times (have many customers with this server type)
Some times hot-swapped while server is running and checked in Array config util that all is good.
And other times, I have shut the server down and swapped.
One way better\ safer than the other?