Can you make "offline" ssd with grub

Question

I have an SSD with Ubuntu where GRUB is located (I think it should be there because I installed grub when I was on Ubuntu). I also have nvme ssd with Windows, and another hdd used by that windows as a storage. My whole partition system is kind of a mess because I ran boot repair utility after installing Windows on my nvme ssd (because the old grub installation got broken after that, you can check my previous question for more details if you want because it's still wasn't answered, I would appreciate if someone will answer it too), but this time the question is another:

I turned off my HDD on Windows disk management utility (pressed "go offline" on that HDD) because I don't use it that often, so I'm hoping to save some power by turning it off. Can I do the same with my SSD? I'm asking because when I'm loading I'm choosing Windows from grub, and I think that GRUB is located on the Ubuntu SSD (because it's also the first option in UEFI). Will turning it off while I'm on Windows break anything, if I already logged into Windows? Thanks in advance.

If it helps, I can make a screenshot with my disks partitions if it's needed, just tell me what to run and screen.

Answer 1

Most likely it won't cause any problem. The "offline" setting in Disk Management applies only to the running Windows. It will NOT stop your UEFI firmware from being able to execute grub or even the Windows Boot Manager. It basicially means to unmount and avoid mounting any (Windows) filesystems / volumes on the drive so that no filesystem level access will be allowed (but lower level access like block level access and SCSI level access will still be available AFAIK, so you could still potentially wipe / overwrite the drive with certain applications even when a drive is offline). It might be worth mentioning that you are required to set the drive to offline when you SCSI passthrough it to a Hyper-V VM. (I don't know if you still need to do it manually or Hyper-V will do it dynamically / automatically for you.)

The only case that I could think of in which it could cause problem is that Windows shares the EFI system partition on that Linux drive. In that case it can prevent e.g. Windows Updates from making necessary changes to the BCD or so. But then I suspect Windows will not allow you set the drive offline in that case.

I myself would disable drive (or even the "controller", like in the case of NVMe or USB) in Device Manager instead (of course I mean when "offline" is fine), although it's way easier to have the wrong drive/device disabled there. That would in turn prevent essentially (or literally?) all access to the drive. (AFAIK, literally you need to enable it back before you get access to it on any level.) That might work better as well if it's about powering. (I'm not going to bother either judging or endorsing whether it could do you any good or harm in terms of powering.)

P.S. Note that "mounting" mentioned above is probably not the same thing as mount in mountvol. AFAIK mountvol is similar or perhaps equivalent to assigning a drive letter with e.g. diskpart. But AFAIK, at least in special case like the EFI system partition, a filesystem is still "mounted" (in the sense that filesystem level access can be performed "behind the scene") even when a volume has no drive letter assigned.