Leaving them powered off but plugged in will do them no harm, provided you are protecting them from electrical events (surge protection, etc.).  There is also nothing wrong with letting it sit unplugged either.  Leaving it unplugged "may" drain the RAID battery, so if you have a RAID battery, just know you will likely need to run the storage for up to 24 hours to recharge the battery.  They should also be stored in near the same environment (temp, humidity, etc.) as if they were operating.
Hi, We have following four Dell servers and they were bought for specific system 2 X R710 2 X R610 Now, I have been asked my managament to shut down these servers as there will be no implementatio of system for a while. I am wondering it is okay or a good reason to shut down servers as they are consuming power? Can anyone please suggest me on this?   Cheers RutledgeIT
Is it okay to keep server down?