There is "Offline" menu in Disk Management. If I click that, the disk becomes offline and not accessible. My question is that, does "offline" actually turn off (spin down) the disk for good (until the system reboots)? Or the physical disk is still spinning (or awake from time to time) but just inaccessible to softwares running on the system?
What about the logical disk is a RAID0? Does it also turn off the physical disks?
In case someone asks me "Why would you do that", there are disks I seldomly use, so I would like to turn it off when it is not used both for saving power and for data protection (unless the hacker got the privilege to make the disk on-line). I could use external disk enclosures but they cannot be remotely turned on/off and requires external power suppliers, plus they are not free.
Best Answer
No, taking a disk offline just makes it unmountable it does not change the power state.
Can you clarify what you mean by if the logical disk is RAID0? Do you mean if the physical disk is part of a RAID array, will offlining the disk offline the whole array? No, if you have a dynamic disk setup in RAID0, offlining the disk will fail the array, if Windows will even still let you do that.
You should replace the drives with power saving drives, such as WD Green drives, if you're concerned about power usage.